diff --git a/httprunner/client.py b/httprunner/client.py
index 0f9e4d9a..1a6c1af6 100644
--- a/httprunner/client.py
+++ b/httprunner/client.py
@@ -1,20 +1,17 @@
 # encoding: utf-8
 
-import re
 import time
 
 import requests
 import urllib3
 from httprunner import logger
-from httprunner.exceptions import ParamsError
+from httprunner.utils import build_url
 from requests import Request, Response
 from requests.exceptions import (InvalidSchema, InvalidURL, MissingSchema,
                                  RequestException)
 
 urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)
 
-absolute_http_url_regexp = re.compile(r"^https?://", re.I)
-
 
 class ApiResponse(Response):
 
@@ -42,15 +39,6 @@ class HttpSession(requests.Session):
         self.base_url = base_url if base_url else ""
         self.init_meta_data()
 
-    def _build_url(self, path):
-        """ prepend url with hostname unless it's already an absolute URL """
-        if absolute_http_url_regexp.match(path):
-            return path
-        elif self.base_url:
-            return "{}/{}".format(self.base_url.rstrip("/"), path.lstrip("/"))
-        else:
-            raise ParamsError("base url missed!")
-
     def init_meta_data(self):
         """ initialize meta_data, it will store detail data of request and response
         """
@@ -125,7 +113,7 @@ class HttpSession(requests.Session):
         self.meta_data["request"]["start_timestamp"] = time.time()
 
         # prepend url with hostname unless it's already an absolute URL
-        url = self._build_url(url)
+        url = build_url(self.base_url, url)
 
         kwargs.setdefault("timeout", 120)
         response = self._send_request_safe_mode(method, url, **kwargs)
diff --git a/httprunner/parser.py b/httprunner/parser.py
index 63aac7d8..e764b048 100644
--- a/httprunner/parser.py
+++ b/httprunner/parser.py
@@ -609,9 +609,12 @@ def _extend_with_api(teststep_dict, api_def_dict):
     # TODO: merge & override request
     teststep_dict["request"] = api_def_dict.pop("request", {})
     # base_url
-    base_url = teststep_dict.pop("base_url", None)
-    if base_url:
-        teststep_dict["request"]["url"] = "{}/{}".format(base_url.rstrip("/"), teststep_dict["request"]["url"].lstrip("/"))
+    if "base_url" in teststep_dict:
+        base_url = teststep_dict.pop("base_url")
+        teststep_dict["request"]["url"] = utils.build_url(
+            base_url,
+            teststep_dict["request"]["url"]
+        )
 
     # verify
     if "verify" in teststep_dict:
@@ -744,8 +747,9 @@ def __parse_teststeps(teststeps, config, project_mapping):
 
     for teststep in teststeps:
 
-        # priority teststep > config
-        teststep.setdefault("base_url", config_base_url)
+        # base_url & verify: priority teststep > config
+        if config_base_url:
+            teststep.setdefault("base_url", config_base_url)
         teststep.setdefault("verify", config_verify)
 
         if "testcase_def" in teststep:
@@ -776,6 +780,10 @@ def __parse_teststeps(teststeps, config, project_mapping):
             _parse_testcase(teststep, project_mapping)
 
         else:
+            # teststep is API test, has two cases.
+            # (1) teststep has API reference
+            # (2) teststep is defined directly
+
             # 1, config => teststeps
             # override teststep variables
             teststep["variables"] = utils.extend_variables(
@@ -794,14 +802,18 @@ def __parse_teststeps(teststeps, config, project_mapping):
                 pass
 
             if "api_def" in teststep:
+                # case (1)
                 # 2, teststep => api
                 api_def_dict = teststep.pop("api_def")
                 _extend_with_api(teststep, api_def_dict)
             else:
-                # base_url
-                base_url = teststep.pop("base_url", None)
-                if base_url:
-                    teststep["request"]["url"] = "{}/{}".format(base_url.rstrip("/"), teststep["request"]["url"].lstrip("/"))
+                # case (2)
+                if "base_url" in teststep:
+                    base_url = teststep.pop("base_url")
+                    teststep["request"]["url"] = utils.build_url(
+                        base_url,
+                        teststep["request"]["url"]
+                    )
 
 
 def _parse_testcase(testcase, project_mapping):
diff --git a/httprunner/utils.py b/httprunner/utils.py
index dfea2059..069b6272 100644
--- a/httprunner/utils.py
+++ b/httprunner/utils.py
@@ -6,11 +6,15 @@ import io
 import itertools
 import json
 import os.path
+import re
 import string
 from datetime import datetime
 
 from httprunner import exceptions, logger
 from httprunner.compat import OrderedDict, basestring, is_py2
+from httprunner.exceptions import ParamsError
+
+absolute_http_url_regexp = re.compile(r"^https?://", re.I)
 
 
 def set_os_environ(variables_mapping):
@@ -48,6 +52,16 @@ def get_os_environ(variable_name):
         raise exceptions.EnvNotFound(variable_name)
 
 
+def build_url(base_url, path):
+    """ prepend url with hostname unless it's already an absolute URL """
+    if absolute_http_url_regexp.match(path):
+        return path
+    elif base_url:
+        return "{}/{}".format(base_url.rstrip("/"), path.lstrip("/"))
+    else:
+        raise ParamsError("base url missed!")
+
+
 def query_json(json_content, query, delimiter='.'):
     """ Do an xpath-like query with json_content.
     @param (dict/list/string) json_content