diff --git a/.github/workflows/integration_test.yml b/.github/workflows/integration_test.yml
index bc5b0ed4..79f3f676 100644
--- a/.github/workflows/integration_test.yml
+++ b/.github/workflows/integration_test.yml
@@ -3,7 +3,7 @@ name: integration_test
 on:
   push:
     branches:
-    - master
+    - dev
   pull_request:
     branches:
     - master
diff --git a/.github/workflows/unittest.yml b/.github/workflows/unittest.yml
index dddc5860..d7454f60 100644
--- a/.github/workflows/unittest.yml
+++ b/.github/workflows/unittest.yml
@@ -3,7 +3,7 @@ name: unittest
 on:
   push:
     branches:
-    - master
+    - dev
   pull_request:
     branches:
     - master
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 5bd0fc5e..9b7327b8 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -1,5 +1,17 @@
 # Release History
 
+## 3.1.3 (2020-07-06)
+
+**Added**
+
+- feat: implement `parameters` feature
+
+**Fixed**
+
+- fix: validate with variable or function whose evaluation result is "" or not text
+- fix: raise TestCaseFormatError if teststep validate invalid
+- fix: raise TestCaseFormatError if ref testcase is invalid
+
 ## 3.1.2 (2020-06-29)
 
 **Fixed**
diff --git a/examples/httpbin/basic_test.py b/examples/httpbin/basic_test.py
index f541798f..78a39bef 100644
--- a/examples/httpbin/basic_test.py
+++ b/examples/httpbin/basic_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: basic.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseBasic(HttpRunner):
+
     config = Config("basic test with httpbin").base_url("https://httpbin.org/")
 
     teststeps = [
diff --git a/examples/httpbin/hooks_test.py b/examples/httpbin/hooks_test.py
index 86a1b0d7..6ec448e9 100644
--- a/examples/httpbin/hooks_test.py
+++ b/examples/httpbin/hooks_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: hooks.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseHooks(HttpRunner):
+
     config = Config("basic test with httpbin").base_url("${get_httpbin_server()}")
 
     teststeps = [
diff --git a/examples/httpbin/load_image_test.py b/examples/httpbin/load_image_test.py
index 47b05af1..f2785770 100644
--- a/examples/httpbin/load_image_test.py
+++ b/examples/httpbin/load_image_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: load_image.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseLoadImage(HttpRunner):
+
     config = Config("load images").base_url("${get_httpbin_server()}")
 
     teststeps = [
diff --git a/examples/httpbin/upload_test.py b/examples/httpbin/upload_test.py
index cdec89fd..0d4ccd89 100644
--- a/examples/httpbin/upload_test.py
+++ b/examples/httpbin/upload_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: upload.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseUpload(HttpRunner):
+
     config = Config("test upload file with httpbin").base_url("${get_httpbin_server()}")
 
     teststeps = [
diff --git a/examples/httpbin/validate_test.py b/examples/httpbin/validate_test.py
index ed15c14d..9de43c70 100644
--- a/examples/httpbin/validate_test.py
+++ b/examples/httpbin/validate_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: validate.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseValidate(HttpRunner):
+
     config = Config("basic test with httpbin").base_url("http://httpbin.org/")
 
     teststeps = [
diff --git a/examples/postman_echo/debugtalk.py b/examples/postman_echo/debugtalk.py
index d28b829b..c0b2aebb 100644
--- a/examples/postman_echo/debugtalk.py
+++ b/examples/postman_echo/debugtalk.py
@@ -4,6 +4,7 @@ from httprunner import __version__
 def get_httprunner_version():
     return __version__
 
+
 def sum_two(m, n):
     return m + n
 
@@ -18,3 +19,7 @@ def get_testsuite_config_variables():
 
 def get_app_version():
     return [3.1, 3.0]
+
+
+def calculate_two_nums(a, b=1):
+    return [a + b, b - a]
diff --git a/examples/postman_echo/request_methods/demo_testsuite_yml/request_with_functions_test.py b/examples/postman_echo/request_methods/demo_testsuite_yml/request_with_functions_test.py
index 50eb0cc8..df68aa1c 100644
--- a/examples/postman_echo/request_methods/demo_testsuite_yml/request_with_functions_test.py
+++ b/examples/postman_echo/request_methods/demo_testsuite_yml/request_with_functions_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: request_methods/request_with_functions.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseRequestWithFunctions(HttpRunner):
+
     config = (
         Config("request with functions")
         .variables(
diff --git a/examples/postman_echo/request_methods/demo_testsuite_yml/request_with_testcase_reference_test.py b/examples/postman_echo/request_methods/demo_testsuite_yml/request_with_testcase_reference_test.py
index 2d131814..99b6e3a3 100644
--- a/examples/postman_echo/request_methods/demo_testsuite_yml/request_with_testcase_reference_test.py
+++ b/examples/postman_echo/request_methods/demo_testsuite_yml/request_with_testcase_reference_test.py
@@ -1,11 +1,13 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: request_methods/request_with_testcase_reference.yml
 
+
 import sys
 from pathlib import Path
 
 sys.path.insert(0, str(Path(__file__).parent.parent))
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 from request_methods.request_with_functions_test import (
@@ -14,6 +16,7 @@ from request_methods.request_with_functions_test import (
 
 
 class TestCaseRequestWithTestcaseReference(HttpRunner):
+
     config = (
         Config("request with referenced testcase")
         .variables(
diff --git a/examples/postman_echo/request_methods/hardcode_test.py b/examples/postman_echo/request_methods/hardcode_test.py
index 70e5e3c9..324d5202 100644
--- a/examples/postman_echo/request_methods/hardcode_test.py
+++ b/examples/postman_echo/request_methods/hardcode_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: request_methods/hardcode.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseHardcode(HttpRunner):
+
     config = (
         Config("request methods testcase in hardcode")
         .base_url("https://postman-echo.com")
diff --git a/examples/postman_echo/request_methods/request_with_functions_test.py b/examples/postman_echo/request_methods/request_with_functions_test.py
index 996eed64..4bbeeb6e 100644
--- a/examples/postman_echo/request_methods/request_with_functions_test.py
+++ b/examples/postman_echo/request_methods/request_with_functions_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: request_methods/request_with_functions.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseRequestWithFunctions(HttpRunner):
+
     config = (
         Config("request methods testcase with functions")
         .variables(
diff --git a/examples/postman_echo/request_methods/request_with_parameters_test.py b/examples/postman_echo/request_methods/request_with_parameters_test.py
new file mode 100644
index 00000000..5f90c15d
--- /dev/null
+++ b/examples/postman_echo/request_methods/request_with_parameters_test.py
@@ -0,0 +1,56 @@
+# NOTE: Generated By HttpRunner v3.1.3
+# FROM: request_methods/request_with_parameters.yml
+
+
+import pytest
+from httprunner import Parameters
+
+
+from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
+
+
+class TestCaseRequestWithParameters(HttpRunner):
+    @pytest.mark.parametrize(
+        "param",
+        Parameters(
+            {
+                "user_agent": ["iOS/10.1", "iOS/10.2"],
+                "username-password": "${parameterize(request_methods/account.csv)}",
+                "app_version": "${get_app_version()}",
+            }
+        ),
+    )
+    def test_start(self, param):
+        super().test_start(param)
+
+    config = (
+        Config("request methods testcase: validate with parameters")
+        .variables(**{"app_version": "f1"})
+        .base_url("https://postman-echo.com")
+        .verify(False)
+    )
+
+    teststeps = [
+        Step(
+            RunRequest("get with params")
+            .with_variables(
+                **{
+                    "foo1": "$username",
+                    "foo2": "$password",
+                    "sum_v": "${sum_two(1, $app_version)}",
+                }
+            )
+            .get("/get")
+            .with_params(**{"foo1": "$foo1", "foo2": "$foo2", "sum_v": "$sum_v"})
+            .with_headers(**{"User-Agent": "$user_agent,$app_version"})
+            .extract()
+            .with_jmespath("body.args.foo2", "session_foo2")
+            .validate()
+            .assert_equal("status_code", 200)
+            .assert_string_equals("body.args.sum_v", "${sum_two(1, $app_version)}")
+        ),
+    ]
+
+
+if __name__ == "__main__":
+    TestCaseRequestWithParameters().test_start()
diff --git a/examples/postman_echo/request_methods/request_with_testcase_reference_test.py b/examples/postman_echo/request_methods/request_with_testcase_reference_test.py
index 2d57795e..e005713b 100644
--- a/examples/postman_echo/request_methods/request_with_testcase_reference_test.py
+++ b/examples/postman_echo/request_methods/request_with_testcase_reference_test.py
@@ -1,11 +1,13 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: request_methods/request_with_testcase_reference.yml
 
+
 import sys
 from pathlib import Path
 
 sys.path.insert(0, str(Path(__file__).parent.parent))
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 from request_methods.request_with_functions_test import (
@@ -14,6 +16,7 @@ from request_methods.request_with_functions_test import (
 
 
 class TestCaseRequestWithTestcaseReference(HttpRunner):
+
     config = (
         Config("request methods testcase: reference testcase")
         .variables(
diff --git a/examples/postman_echo/request_methods/request_with_variables_test.py b/examples/postman_echo/request_methods/request_with_variables_test.py
index cacc4621..ebaefe52 100644
--- a/examples/postman_echo/request_methods/request_with_variables_test.py
+++ b/examples/postman_echo/request_methods/request_with_variables_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: request_methods/request_with_variables.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseRequestWithVariables(HttpRunner):
+
     config = (
         Config("request methods testcase with variables")
         .variables(**{"foo1": "testcase_config_bar1", "foo2": "testcase_config_bar2"})
diff --git a/examples/postman_echo/request_methods/validate_with_functions_test.py b/examples/postman_echo/request_methods/validate_with_functions_test.py
index 4b67bba5..1a6ca71d 100644
--- a/examples/postman_echo/request_methods/validate_with_functions_test.py
+++ b/examples/postman_echo/request_methods/validate_with_functions_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: request_methods/validate_with_functions.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseValidateWithFunctions(HttpRunner):
+
     config = (
         Config("request methods testcase: validate with functions")
         .variables(**{"foo1": "session_bar1"})
diff --git a/examples/postman_echo/request_methods/validate_with_variables_test.py b/examples/postman_echo/request_methods/validate_with_variables_test.py
index 07f6d5b3..6045dc47 100644
--- a/examples/postman_echo/request_methods/validate_with_variables_test.py
+++ b/examples/postman_echo/request_methods/validate_with_variables_test.py
@@ -1,10 +1,12 @@
-# NOTE: Generated By HttpRunner v3.1.2
+# NOTE: Generated By HttpRunner v3.1.3
 # FROM: request_methods/validate_with_variables.yml
 
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 
 
 class TestCaseValidateWithVariables(HttpRunner):
+
     config = (
         Config("request methods testcase: validate with variables")
         .variables(**{"foo1": "session_bar1"})
diff --git a/httprunner/__init__.py b/httprunner/__init__.py
index 6118a14a..2fd95302 100644
--- a/httprunner/__init__.py
+++ b/httprunner/__init__.py
@@ -1,8 +1,9 @@
-__version__ = "3.1.2"
+__version__ = "3.1.3"
 __description__ = "One-stop solution for HTTP(S) testing."
 
 # import firstly for monkey patch if needed
 from httprunner.ext.locust import main_locusts
+from httprunner.parser import parse_parameters as Parameters
 from httprunner.runner import HttpRunner
 from httprunner.testcase import Config, Step, RunRequest, RunTestCase
 
@@ -14,4 +15,5 @@ __all__ = [
     "Step",
     "RunRequest",
     "RunTestCase",
+    "Parameters",
 ]
diff --git a/httprunner/compat.py b/httprunner/compat.py
index 21f7a809..dd6b526e 100644
--- a/httprunner/compat.py
+++ b/httprunner/compat.py
@@ -182,6 +182,10 @@ def _ensure_step_attachment(step: Dict) -> Dict:
         test_dict["export"] = step["export"]
 
     if "validate" in step:
+        if not isinstance(step["validate"], List):
+            raise exceptions.TestCaseFormatError(
+                f'Invalid teststep validate: {step["validate"]}'
+            )
         test_dict["validate"] = _convert_validators(step["validate"])
 
     if "validate_script" in step:
diff --git a/httprunner/ext/har2case/core.py b/httprunner/ext/har2case/core.py
index 7535270b..31796862 100644
--- a/httprunner/ext/har2case/core.py
+++ b/httprunner/ext/har2case/core.py
@@ -251,7 +251,12 @@ class HarParser(object):
 
             encoding = resp_content_dict.get("encoding")
             if encoding and encoding == "base64":
-                content = base64.b64decode(text).decode("utf-8")
+                content = base64.b64decode(text)
+                try:
+                    content = content.decode("utf-8")
+                except UnicodeDecodeError:
+                    logger.warning(f"failed to decode base64 content with utf-8 !")
+                    return
             else:
                 content = text
 
diff --git a/httprunner/make.py b/httprunner/make.py
index ada16813..13b95460 100644
--- a/httprunner/make.py
+++ b/httprunner/make.py
@@ -37,23 +37,31 @@ pytest_files_run_set: Set = set()
 __TEMPLATE__ = jinja2.Template(
     """# NOTE: Generated By HttpRunner v{{ version }}
 # FROM: {{ testcase_path }}
+
 {% if imports_list and diff_levels > 0 %}
 import sys
 from pathlib import Path
-
-sys.path.insert(0, str(Path(__file__)
-{% for _ in range(diff_levels) %}
-.parent
-{% endfor %}
-))
+sys.path.insert(0, str(Path(__file__){% for _ in range(diff_levels) %}.parent{% endfor %}))
 {% endif %}
+
+{% if parameters %}
+import pytest
+from httprunner import Parameters
+{% endif %}
+
 from httprunner import HttpRunner, Config, Step, RunRequest, RunTestCase
 {% for import_str in imports_list %}
 {{ import_str }}
 {% endfor %}
 
 class {{ class_name }}(HttpRunner):
-    {{ customization_test_start }}
+
+    {% if parameters %}
+    @pytest.mark.parametrize("param", Parameters({{parameters}}))
+    def test_start(self, param):
+        super().test_start(param)
+    {% endif %}
+
     config = {{ config_chain_style }}
 
     teststeps = [
@@ -367,6 +375,9 @@ def make_testcase(testcase: Dict, dir_path: Text = None) -> Text:
         ref_testcase_path = __ensure_absolute(teststep["testcase"])
         test_content = load_test_file(ref_testcase_path)
 
+        if not isinstance(test_content, Dict):
+            raise exceptions.TestCaseFormatError(f"Invalid teststep: {teststep}")
+
         # api in v2 format, convert to v3 testcase
         if "request" in test_content and "name" in test_content:
             test_content = ensure_testcase_v3_api(test_content)
@@ -408,7 +419,7 @@ def make_testcase(testcase: Dict, dir_path: Text = None) -> Text:
         "class_name": f"TestCase{testcase_cls_name}",
         "imports_list": imports_list,
         "config_chain_style": make_config_chain_style(config),
-        "customization_test_start": make_test_start_style(config),
+        "parameters": config.get("parameters"),
         "teststeps_chain_style": [
             make_teststep_chain_style(step) for step in teststeps
         ],
@@ -608,22 +619,3 @@ def init_make_parser(subparsers):
     )
 
     return parser
-
-
-def make_test_start_style(config: Dict) -> Text:
-    test_start_style = ""
-    if "parameters" in config.keys():
-        params = config["parameters"]
-        test_start_style = f"""
-    import pytest
-    from httprunner.parser import parse_parameters
-    
-    param = [{params}]
-
-    @pytest.mark.parametrize('parametrize', parse_parameters(param))
-    def test_start(self, parametrize):
-        super().test_start(parametrize)
-        """
-    else:
-        pass
-    return test_start_style
\ No newline at end of file
diff --git a/httprunner/parser.py b/httprunner/parser.py
index d5178356..f7fd4f25 100644
--- a/httprunner/parser.py
+++ b/httprunner/parser.py
@@ -1,7 +1,7 @@
 import ast
 import builtins
 import re
-from typing import Any, Set, Text, Callable, List, Dict
+from typing import Any, Set, Text, Callable, List, Dict, Union
 
 from loguru import logger
 from sentry_sdk import capture_exception
@@ -465,51 +465,44 @@ def parse_variables_mapping(
     return parsed_variables
 
 
-def parse_parameters(parameters, variables_mapping=None, functions_mapping=None):
+def parse_parameters(parameters: Dict,) -> List[Dict]:
     """ parse parameters and generate cartesian product.
 
     Args:
-        parameters (list) parameters: parameter name and value in list
+        parameters (Dict) parameters: parameter name and value mapping
             parameter value may be in three types:
                 (1) data list, e.g. ["iOS/10.1", "iOS/10.2", "iOS/10.3"]
                 (2) call built-in parameterize function, "${parameterize(account.csv)}"
                 (3) call custom function in debugtalk.py, "${gen_app_version()}"
 
-        variables_mapping (dict): variables mapping loaded from testcase config
-        functions_mapping (dict): functions mapping loaded from debugtalk.py
-
     Returns:
         list: cartesian product list
 
     Examples:
-        >>> parameters = [
-            {"user_agent": ["iOS/10.1", "iOS/10.2", "iOS/10.3"]},
-            {"username-password": "${parameterize(account.csv)}"},
-            {"app_version": "${gen_app_version()}"}
-        ]
+        >>> parameters = {
+            "user_agent": ["iOS/10.1", "iOS/10.2", "iOS/10.3"],
+            "username-password": "${parameterize(account.csv)}",
+            "app_version": "${gen_app_version()}",
+        }
         >>> parse_parameters(parameters)
 
     """
-    variables_mapping = variables_mapping or {}
-    functions_mapping = functions_mapping or {}
-    parsed_parameters_list = []
+    parsed_parameters_list: List[List[Dict]] = []
 
     # load project_meta functions
-    from httprunner.loader import load_project_meta
-    project_meta = load_project_meta("")
-    functions_mapping.update(project_meta.functions)
+    project_meta = loader.load_project_meta("")
+    functions_mapping = project_meta.functions
 
-    parameters = utils.ensure_mapping_format(parameters)
     for parameter_name, parameter_content in parameters.items():
         parameter_name_list = parameter_name.split("-")
 
-        if isinstance(parameter_content, list):
+        if isinstance(parameter_content, List):
             # (1) data list
             # e.g. {"app_version": ["2.8.5", "2.8.6"]}
             #       => [{"app_version": "2.8.5", "app_version": "2.8.6"}]
             # e.g. {"username-password": [["user1", "111111"], ["test2", "222222"]}
             #       => [{"username": "user1", "password": "111111"}, {"username": "user2", "password": "222222"}]
-            parameter_content_list = []
+            parameter_content_list: List[Dict] = []
             for parameter_item in parameter_content:
                 if not isinstance(parameter_item, (list, tuple)):
                     # "2.8.5" => ["2.8.5"]
@@ -518,25 +511,21 @@ def parse_parameters(parameters, variables_mapping=None, functions_mapping=None)
                 # ["app_version"], ["2.8.5"] => {"app_version": "2.8.5"}
                 # ["username", "password"], ["user1", "111111"] => {"username": "user1", "password": "111111"}
                 parameter_content_dict = dict(zip(parameter_name_list, parameter_item))
-
                 parameter_content_list.append(parameter_content_dict)
-        else:
-            # (2) & (3)
-            parsed_variables_mapping = parse_variables_mapping(
-                variables_mapping,
-                functions_mapping
-            )
-            parsed_parameter_content = parse_data(
-                parameter_content,
-                parsed_variables_mapping,
-                functions_mapping
-            )
-            if not isinstance(parsed_parameter_content, list):
-                raise exceptions.ParamsError(f"{parsed_parameter_content} parameters syntax error!")
 
-            parameter_content_list = []
+        elif isinstance(parameter_content, Text):
+            # (2) & (3)
+            parsed_parameter_content: List = parse_data(
+                parameter_content, {}, functions_mapping
+            )
+            if not isinstance(parsed_parameter_content, List):
+                raise exceptions.ParamsError(
+                    f"parameters content should be in List type, got {parsed_parameter_content} for {parameter_content}"
+                )
+
+            parameter_content_list: List[Dict] = []
             for parameter_item in parsed_parameter_content:
-                if isinstance(parameter_item, dict):
+                if isinstance(parameter_item, Dict):
                     # get subset by parameter name
                     # {"app_version": "${gen_app_version()}"}
                     # gen_app_version() => [{'app_version': '2.8.5'}, {'app_version': '2.8.6'}]
@@ -545,20 +534,39 @@ def parse_parameters(parameters, variables_mapping=None, functions_mapping=None)
                     #       {"username": "user1", "password": "111111"},
                     #       {"username": "user2", "password": "222222"}
                     # ]
-                    parameter_dict = {key: parameter_item[key] for key in parameter_name_list}
-    #             elif isinstance(parameter_item, (list, tuple)):
-    #                 # {"username-password": "${get_account()}"}
-    #                 # get_account() => [("user1", "111111"), ("user2", "222222")]
-    #                 parameter_dict = dict(zip(parameter_name_list, parameter_item))
+                    parameter_dict: Dict = {
+                        key: parameter_item[key] for key in parameter_name_list
+                    }
+                elif isinstance(parameter_item, (List, tuple)):
+                    if len(parameter_name_list) == len(parameter_item):
+                        # {"username-password": "${get_account()}"}
+                        # get_account() => [("user1", "111111"), ("user2", "222222")]
+                        parameter_dict = dict(zip(parameter_name_list, parameter_item))
+                    else:
+                        raise exceptions.ParamsError(
+                            f"parameter names length are not equal to value length.\n"
+                            f"parameter names: {parameter_name_list}\n"
+                            f"parameter values: {parameter_item}"
+                        )
                 elif len(parameter_name_list) == 1:
                     # {"user_agent": "${get_user_agent()}"}
                     # get_user_agent() => ["iOS/10.1", "iOS/10.2"]
-                    parameter_dict = {
-                        parameter_name_list[0]: parameter_item
-                    }
+                    # parameter_dict will get: {"user_agent": "iOS/10.1", "user_agent": "iOS/10.2"}
+                    parameter_dict = {parameter_name_list[0]: parameter_item}
+                else:
+                    raise exceptions.ParamsError(
+                        f"Invalid parameter names and values:\n"
+                        f"parameter names: {parameter_name_list}\n"
+                        f"parameter values: {parameter_item}"
+                    )
 
                 parameter_content_list.append(parameter_dict)
 
+        else:
+            raise exceptions.ParamsError(
+                f"parameter content should be List or Text(variables or functions call), got {parameter_content}"
+            )
+
         parsed_parameters_list.append(parameter_content_list)
 
     return utils.gen_cartesian_product(*parsed_parameters_list)
diff --git a/httprunner/response.py b/httprunner/response.py
index 6b129a97..7de9bd03 100644
--- a/httprunner/response.py
+++ b/httprunner/response.py
@@ -2,12 +2,13 @@ from typing import Dict, Text, Any, NoReturn
 
 import jmespath
 import requests
+from jmespath.exceptions import JMESPathError
 from loguru import logger
 
 from httprunner import exceptions
 from httprunner.exceptions import ValidationFailure, ParamsError
-from httprunner.parser import parse_data, parse_string_value, get_mapping_function
 from httprunner.models import VariablesMapping, Validators, FunctionsMapping
+from httprunner.parser import parse_data, parse_string_value, get_mapping_function
 
 
 def get_uniform_comparator(comparator: Text):
@@ -143,14 +144,25 @@ class ResponseObject(object):
         self.__dict__[key] = value
         return value
 
-    @property
-    def resp_obj_meta(self):
-        return {
+    def _search_jmespath(self, expr: Text) -> Any:
+        resp_obj_meta = {
             "status_code": self.status_code,
             "headers": self.headers,
             "cookies": self.cookies,
             "body": self.body,
         }
+        try:
+            check_value = jmespath.search(expr, resp_obj_meta)
+        except JMESPathError as ex:
+            logger.error(
+                f"failed to search with jmespath\n"
+                f"expression: {expr}\n"
+                f"data: {resp_obj_meta}\n"
+                f"exception: {ex}"
+            )
+            raise
+
+        return check_value
 
     def extract(self, extractors: Dict[Text, Text]) -> Dict[Text, Any]:
         if not extractors:
@@ -158,7 +170,7 @@ class ResponseObject(object):
 
         extract_mapping = {}
         for key, field in extractors.items():
-            field_value = jmespath.search(field, self.resp_obj_meta)
+            field_value = self._search_jmespath(field)
             extract_mapping[key] = field_value
 
         logger.info(f"extract mapping: {extract_mapping}")
@@ -197,7 +209,11 @@ class ResponseObject(object):
                 )
                 check_item = parse_string_value(check_item)
 
-            check_value = jmespath.search(check_item, self.resp_obj_meta)
+            if check_item and isinstance(check_item, Text):
+                check_value = self._search_jmespath(check_item)
+            else:
+                # variable or function evaluation result is "" or not text
+                check_value = check_item
 
             # comparator
             assert_method = u_validator["assert"]
diff --git a/httprunner/runner.py b/httprunner/runner.py
index d2129f03..64abf690 100644
--- a/httprunner/runner.py
+++ b/httprunner/runner.py
@@ -421,7 +421,7 @@ class HttpRunner(object):
             step_datas=self.__step_datas,
         )
 
-    def test_start(self, parametrize=None) -> "HttpRunner":
+    def test_start(self, param: Dict = None) -> "HttpRunner":
         """main entrance, discovered by pytest"""
         self.__init_tests__()
         self.__project_meta = self.__project_meta or load_project_meta(
@@ -435,8 +435,8 @@ class HttpRunner(object):
 
         # parse config name
         config_variables = self.__config.variables
-        if parametrize:
-            config_variables.update(parametrize)
+        if param:
+            config_variables.update(param)
         config_variables.update(self.__session_variables)
         self.__config.name = parse_data(
             self.__config.name, config_variables, self.__project_meta.functions
diff --git a/httprunner/testcase.py b/httprunner/testcase.py
index f8044d95..86d1554f 100644
--- a/httprunner/testcase.py
+++ b/httprunner/testcase.py
@@ -159,7 +159,7 @@ class StepRequestValidation(object):
         return self
 
     def assert_string_equals(
-        self, jmes_path: Text, expected_value: int, message: Text = ""
+        self, jmes_path: Text, expected_value: Any, message: Text = ""
     ) -> "StepRequestValidation":
         self.__step_context.validators.append(
             {"string_equals": [jmes_path, expected_value, message]}
diff --git a/httprunner/utils.py b/httprunner/utils.py
index 597c728c..eeb7e0a0 100644
--- a/httprunner/utils.py
+++ b/httprunner/utils.py
@@ -6,7 +6,7 @@ import platform
 import uuid
 from multiprocessing import Queue
 import itertools
-from typing import Dict, List, Any
+from typing import Dict, List, Any, Union, Text
 
 import sentry_sdk
 from loguru import logger
@@ -223,42 +223,7 @@ def is_support_multiprocessing() -> bool:
         return False
 
 
-def ensure_mapping_format(variables):
-    """ ensure variables are in mapping format.
-
-    Args:
-        variables (list/dict): original variables
-
-    Returns:
-        dict: ensured variables in dict format
-
-    Examples:
-        >>> variables = [
-                {"a": 1},
-                {"b": 2}
-            ]
-        >>> print(ensure_mapping_format(variables))
-            {
-                "a": 1,
-                "b": 2
-            }
-
-    """
-    if isinstance(variables, list):
-        variables_dict = {}
-        for map_dict in variables:
-            variables_dict.update(map_dict)
-
-        return variables_dict
-
-    elif isinstance(variables, dict):
-        return variables
-
-    else:
-        raise exceptions.ParamsError("variables format error!")
-
-
-def gen_cartesian_product(*args):
+def gen_cartesian_product(*args: List[Dict]) -> List[Dict]:
     """ generate cartesian product for lists
 
     Args:
diff --git a/pyproject.toml b/pyproject.toml
index e300377b..e207aa77 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "httprunner"
-version = "3.1.2"
+version = "3.1.3"
 description = "One-stop solution for HTTP(S) testing."
 license = "Apache-2.0"
 readme = "README.md"
diff --git a/tests/make_test.py b/tests/make_test.py
index e8e8fb15..56199b8f 100644
--- a/tests/make_test.py
+++ b/tests/make_test.py
@@ -1,6 +1,7 @@
 import os
 import unittest
 
+from httprunner import loader
 from httprunner.make import (
     main_make,
     convert_testcase_path,
@@ -9,9 +10,7 @@ from httprunner.make import (
     make_teststep_chain_style,
     pytest_files_run_set,
     ensure_file_abs_path_valid,
-    make_test_start_style
 )
-from httprunner import loader
 
 
 class TestMake(unittest.TestCase):
@@ -215,26 +214,3 @@ from request_methods.request_with_functions_test import (
             teststep_chain_style,
             """Step(RunRequest("get with params").with_variables(**{'foo1': 'bar1', 'foo2': 123, 'sum_v': '${sum_two(1, 2)}'}).get("/get").with_params(**{'foo1': '$foo1', 'foo2': '$foo2', 'sum_v': '$sum_v'}).with_headers(**{'User-Agent': 'HttpRunner/${get_httprunner_version()}'}).extract().with_jmespath('body.args.foo1', 'session_foo1').with_jmespath('body.args.foo2', 'session_foo2').validate().assert_equal("status_code", 200).assert_equal("body.args.sum_v", "3"))""",
         )
-
-    def test_make_test_start_style(self):
-        params = {
-            "user_agent": ["iOS/10.1", "iOS/10.2"],
-            "username-password": "${parameterize(request_methods/account.csv)}",
-            "app_version": "${get_app_version()}",
-        }
-        config = {
-            "parameters": params
-        }
-        self.assertEqual(
-            make_test_start_style(config),
-            f"""
-    import pytest
-    from httprunner.parser import parse_parameters
-    
-    param = [{params}]
-
-    @pytest.mark.parametrize('parametrize', parse_parameters(param))
-    def test_start(self, parametrize):
-        super().test_start(parametrize)
-        """
-        )
\ No newline at end of file
diff --git a/tests/parser_test.py b/tests/parser_test.py
index 96d3cd20..e1eef7fa 100644
--- a/tests/parser_test.py
+++ b/tests/parser_test.py
@@ -1,9 +1,10 @@
+import os
 import time
 import unittest
 
 from httprunner import parser
 from httprunner.exceptions import VariableNotFound, FunctionNotFound
-from httprunner.parser import regex_findall_variables
+from httprunner.loader import load_project_meta
 
 
 class TestParserBasic(unittest.TestCase):
@@ -27,17 +28,19 @@ class TestParserBasic(unittest.TestCase):
         self.assertEqual(parser.parse_string_value("${func}"), "${func}")
 
     def test_regex_findall_variables(self):
-        self.assertEqual(regex_findall_variables("$variable"), ["variable"])
-        self.assertEqual(regex_findall_variables("${variable}123"), ["variable"])
-        self.assertEqual(regex_findall_variables("/blog/$postid"), ["postid"])
-        self.assertEqual(regex_findall_variables("/$var1/$var2"), ["var1", "var2"])
-        self.assertEqual(regex_findall_variables("abc"), [])
-        self.assertEqual(regex_findall_variables("Z:2>1*0*1+1$a"), ["a"])
-        self.assertEqual(regex_findall_variables("Z:2>1*0*1+1$$a"), [])
-        self.assertEqual(regex_findall_variables("Z:2>1*0*1+1$$$a"), ["a"])
-        self.assertEqual(regex_findall_variables("Z:2>1*0*1+1$$$$a"), [])
-        self.assertEqual(regex_findall_variables("Z:2>1*0*1+1$$a$b"), ["b"])
-        self.assertEqual(regex_findall_variables("Z:2>1*0*1+1$$a$$b"), [])
+        self.assertEqual(parser.regex_findall_variables("$variable"), ["variable"])
+        self.assertEqual(parser.regex_findall_variables("${variable}123"), ["variable"])
+        self.assertEqual(parser.regex_findall_variables("/blog/$postid"), ["postid"])
+        self.assertEqual(
+            parser.regex_findall_variables("/$var1/$var2"), ["var1", "var2"]
+        )
+        self.assertEqual(parser.regex_findall_variables("abc"), [])
+        self.assertEqual(parser.regex_findall_variables("Z:2>1*0*1+1$a"), ["a"])
+        self.assertEqual(parser.regex_findall_variables("Z:2>1*0*1+1$$a"), [])
+        self.assertEqual(parser.regex_findall_variables("Z:2>1*0*1+1$$$a"), ["a"])
+        self.assertEqual(parser.regex_findall_variables("Z:2>1*0*1+1$$$$a"), [])
+        self.assertEqual(parser.regex_findall_variables("Z:2>1*0*1+1$$a$b"), ["b"])
+        self.assertEqual(parser.regex_findall_variables("Z:2>1*0*1+1$$a$$b"), [])
 
     def test_extract_variables(self):
         self.assertEqual(parser.extract_variables("$var"), {"var"})
@@ -454,28 +457,91 @@ class TestParserBasic(unittest.TestCase):
         self.assertEqual(parsed_testcase["headers"]["sum"], 3)
 
     def test_parse_parameters_testcase(self):
-        variables = {
-            "user_agent": "chrome",
-            "sum": 5,
+        parameters = {
+            "user_agent": ["iOS/10.1", "iOS/10.2"],
+            "username-password": "${parameterize(request_methods/account.csv)}",
+            "sum": "${calculate_two_nums(1, 2)}",
         }
-        param = [
+        load_project_meta(
+            os.path.join(
+                os.path.dirname(os.path.dirname(__file__)),
+                "examples",
+                "postman_echo",
+                "request_methods",
+            ),
+        )
+        parsed_params = parser.parse_parameters(parameters)
+        self.assertEqual(len(parsed_params), 2 * 3 * 2)
+
+        self.assertIn(
             {
-                "user_agent": ["iOS/10.1", "iOS/10.2"],
-                "username-password": "${parameterize(request_methods/account.csv)}",
-                "sum": "${add_two_nums(1, 2)}",
-            }
-        ]
-
-        functions = {
-            "add_two_nums": lambda a, b=1: [a + b, b-a],
-        }
-
-        parsed_params = parser.parse_parameters(param, variables, functions)
-        self.assertIn({'username': 'test1', 'password': '111111', 'user_agent': 'iOS/10.1', 'sum': 3}, parsed_params)
-        self.assertIn({'username': 'test1', 'password': '111111', 'user_agent': 'iOS/10.1', 'sum': 1}, parsed_params)
-        self.assertIn({'username': 'test1', 'password': '111111', 'user_agent': 'iOS/10.2', 'sum': 3}, parsed_params)
-        self.assertIn({'username': 'test1', 'password': '111111', 'user_agent': 'iOS/10.2', 'sum': 1}, parsed_params)
-        self.assertIn({'username': 'test2', 'password': '222222', 'user_agent': 'iOS/10.1', 'sum': 3}, parsed_params)
-        self.assertIn({'username': 'test2', 'password': '222222', 'user_agent': 'iOS/10.1', 'sum': 1}, parsed_params)
-        self.assertIn({'username': 'test2', 'password': '222222', 'user_agent': 'iOS/10.2', 'sum': 3}, parsed_params)
-        self.assertIn({'username': 'test2', 'password': '222222', 'user_agent': 'iOS/10.2', 'sum': 1}, parsed_params)
+                "username": "test1",
+                "password": "111111",
+                "user_agent": "iOS/10.1",
+                "sum": 3,
+            },
+            parsed_params,
+        )
+        self.assertIn(
+            {
+                "username": "test1",
+                "password": "111111",
+                "user_agent": "iOS/10.1",
+                "sum": 1,
+            },
+            parsed_params,
+        )
+        self.assertIn(
+            {
+                "username": "test1",
+                "password": "111111",
+                "user_agent": "iOS/10.2",
+                "sum": 3,
+            },
+            parsed_params,
+        )
+        self.assertIn(
+            {
+                "username": "test1",
+                "password": "111111",
+                "user_agent": "iOS/10.2",
+                "sum": 1,
+            },
+            parsed_params,
+        )
+        self.assertIn(
+            {
+                "username": "test2",
+                "password": "222222",
+                "user_agent": "iOS/10.1",
+                "sum": 3,
+            },
+            parsed_params,
+        )
+        self.assertIn(
+            {
+                "username": "test2",
+                "password": "222222",
+                "user_agent": "iOS/10.1",
+                "sum": 1,
+            },
+            parsed_params,
+        )
+        self.assertIn(
+            {
+                "username": "test2",
+                "password": "222222",
+                "user_agent": "iOS/10.2",
+                "sum": 3,
+            },
+            parsed_params,
+        )
+        self.assertIn(
+            {
+                "username": "test2",
+                "password": "222222",
+                "user_agent": "iOS/10.2",
+                "sum": 1,
+            },
+            parsed_params,
+        )
diff --git a/tests/response_test.py b/tests/response_test.py
index f6f8e936..7f98cfa3 100644
--- a/tests/response_test.py
+++ b/tests/response_test.py
@@ -28,12 +28,28 @@ class TestResponse(unittest.TestCase):
         self.assertEqual(extract_mapping["var_2"], "Olympia")
 
     def test_validate(self):
-        variables_mapping = {"index": 1}
         self.resp_obj.validate(
             [
                 {"eq": ["body.json.locations[0].name", "Seattle"]},
                 {"eq": ["body.json.locations[0]", {"name": "Seattle", "state": "WA"}]},
+            ],
+        )
+
+    def test_validate_variables(self):
+        variables_mapping = {"index": 1, "var_empty": ""}
+        self.resp_obj.validate(
+            [
                 {"eq": ["body.json.locations[$index].name", "New York"]},
+                {"eq": ["$var_empty", ""]},
             ],
             variables_mapping=variables_mapping,
         )
+
+    def test_validate_functions(self):
+        variables_mapping = {"index": 1}
+        functions_mapping = {"get_num": lambda x: x}
+        self.resp_obj.validate(
+            [{"eq": ["${get_num(0)}", 0]}, {"eq": ["${get_num($index)}", 1]},],
+            variables_mapping=variables_mapping,
+            functions_mapping=functions_mapping,
+        )
diff --git a/tests/utils_test.py b/tests/utils_test.py
index 2d767e05..444c4f3b 100644
--- a/tests/utils_test.py
+++ b/tests/utils_test.py
@@ -126,54 +126,28 @@ class TestUtils(unittest.TestCase):
             {"base_url": "https://httpbin.org", "foo1": "bar1"},
         )
 
-    def test_ensure_mapping_format(self):
-        map_list = [
-            {"a": 1},
-            {"b": 2}
-        ]
-        ordered_dict = utils.ensure_mapping_format(map_list)
-        self.assertIsInstance(ordered_dict, dict)
-        self.assertIn("a", ordered_dict)
-
     def test_cartesian_product_one(self):
-        parameters_content_list = [
-            [
-                {"a": 1},
-                {"a": 2}
-            ]
-        ]
+        parameters_content_list = [[{"a": 1}, {"a": 2}]]
         product_list = utils.gen_cartesian_product(*parameters_content_list)
-        self.assertEqual(
-            product_list,
-            [
-                {"a": 1},
-                {"a": 2}
-            ]
-        )
+        self.assertEqual(product_list, [{"a": 1}, {"a": 2}])
 
     def test_cartesian_product_multiple(self):
         parameters_content_list = [
-            [
-                {"a": 1},
-                {"a": 2}
-            ],
-            [
-                {"x": 111, "y": 112},
-                {"x": 121, "y": 122}
-            ]
+            [{"a": 1}, {"a": 2}],
+            [{"x": 111, "y": 112}, {"x": 121, "y": 122}],
         ]
         product_list = utils.gen_cartesian_product(*parameters_content_list)
         self.assertEqual(
             product_list,
             [
-                {'a': 1, 'x': 111, 'y': 112},
-                {'a': 1, 'x': 121, 'y': 122},
-                {'a': 2, 'x': 111, 'y': 112},
-                {'a': 2, 'x': 121, 'y': 122}
-            ]
+                {"a": 1, "x": 111, "y": 112},
+                {"a": 1, "x": 121, "y": 122},
+                {"a": 2, "x": 111, "y": 112},
+                {"a": 2, "x": 121, "y": 122},
+            ],
         )
 
     def test_cartesian_product_empty(self):
         parameters_content_list = []
         product_list = utils.gen_cartesian_product(*parameters_content_list)
-        self.assertEqual(product_list, [])
\ No newline at end of file
+        self.assertEqual(product_list, [])