diff --git a/examples/postman_echo/request_methods/with_variables.yml b/examples/postman_echo/request_methods/with_variables.yml
index 008dd007..625e240f 100644
--- a/examples/postman_echo/request_methods/with_variables.yml
+++ b/examples/postman_echo/request_methods/with_variables.yml
@@ -10,7 +10,7 @@ teststeps:
     name: get with params
     variables:
         foo1: bar1
-        foo2: bar2
+        foo2: session_bar2
     request:
         method: GET
         url: /get
@@ -19,24 +19,27 @@ teststeps:
             foo2: $foo2
         headers:
             User-Agent: HttpRunner/3.0
+    extract:
+        session_foo2: "body.args.foo2"
     validate:
         - eq: ["status_code", 200]
         - eq: ["body.args.foo1", "session_bar1"]
-        - eq: ["body.args.foo2", "bar2"]
+        - eq: ["body.args.foo2", "session_bar2"]
 -
     name: post raw text
     variables:
         foo1: "hello world"
+        foo3: "$session_foo2"
     request:
         method: POST
         url: /post
         headers:
             User-Agent: HttpRunner/3.0
             Content-Type: "text/plain"
-        data: "This is expected to be sent back as part of response body: $foo1."
+        data: "This is expected to be sent back as part of response body: $foo1-$foo3."
     validate:
         - eq: ["status_code", 200]
-        - eq: ["body.data", "This is expected to be sent back as part of response body: session_bar1."]
+        - eq: ["body.data", "This is expected to be sent back as part of response body: session_bar1-session_bar2."]
 -
     name: post form data
     variables:
diff --git a/examples/postman_echo/request_methods/with_variables_test.py b/examples/postman_echo/request_methods/with_variables_test.py
index c68c99fa..df29953f 100644
--- a/examples/postman_echo/request_methods/with_variables_test.py
+++ b/examples/postman_echo/request_methods/with_variables_test.py
@@ -17,7 +17,7 @@ class TestCaseRequestMethodsWithVariables(TestCaseRunner):
             "name": "get with params",
             "variables": {
                 "foo1": "bar1",
-                "foo2": "bar2"
+                "foo2": "session_bar2"
             },
             "request": {
                 "method": "GET",
@@ -30,21 +30,25 @@ class TestCaseRequestMethodsWithVariables(TestCaseRunner):
                     "User-Agent": "HttpRunner/3.0"
                 }
             },
+            "extract": {
+                "session_foo2": "body.args.foo2"
+            },
             "validate": [
                 {"eq": ["status_code", 200]},
                 {"eq": ["body.args.foo1", "session_bar1"]},
-                {"eq": ["body.args.foo2", "bar2"]}
+                {"eq": ["body.args.foo2", "session_bar2"]}
             ]
         }),
         TestStep(**{
             "name": "post raw text",
             "variables": {
-                "foo1": "hello world"
+                "foo1": "hello world",
+                "foo3": "$session_foo2"
             },
             "request": {
                 "method": "POST",
                 "url": "/post",
-                "data": "This is expected to be sent back as part of response body: $foo1.",
+                "data": "This is expected to be sent back as part of response body: $foo1-$foo3.",
                 "headers": {
                     "User-Agent": "HttpRunner/3.0",
                     "Content-Type": "text/plain"
@@ -52,7 +56,10 @@ class TestCaseRequestMethodsWithVariables(TestCaseRunner):
             },
             "validate": [
                 {"eq": ["status_code", 200]},
-                {"eq": ["body.data", "This is expected to be sent back as part of response body: session_bar1."]},
+                {"eq": [
+                    "body.data",
+                    "This is expected to be sent back as part of response body: session_bar1-session_bar2."
+                ]},
             ]
         }),
         TestStep(**{
diff --git a/httprunner/v3/parser.py b/httprunner/v3/parser.py
index c3365490..9e1b2ad3 100644
--- a/httprunner/v3/parser.py
+++ b/httprunner/v3/parser.py
@@ -3,6 +3,7 @@ from typing import Any, Set, Text
 from typing import Dict
 
 from httprunner.v3 import exceptions
+from httprunner.v3.exceptions import VariableNotFound
 
 absolute_http_url_regexp = re.compile(r"^https?://", re.I)
 
@@ -98,7 +99,10 @@ def parse_string_variables(content, variables_mapping):
     """
     variables_list = extract_variables(content)
     for variable_name in variables_list:
-        variable_value = variables_mapping[variable_name]
+        try:
+            variable_value = variables_mapping[variable_name]
+        except KeyError:
+            raise VariableNotFound(f"{variable_name} not in {variables_mapping}")
 
         # TODO: replace variable label from $var to {{var}}
         if f"${variable_name}" == content:
@@ -158,20 +162,24 @@ def parse_content(content: Any, variables_mapping: Dict[str, Any] = None, functi
     return content
 
 
-def parse_variables_mapping(variables_mapping: Dict[str, Any]):
+def parse_variables_mapping(variables_mapping: Dict[Text, Any]) -> Dict[Text, Any]:
 
-    parsed_variables: Dict[str, Any] = {}
+    parsed_variables: Dict[Text, Any] = {}
 
     while len(parsed_variables) != len(variables_mapping):
         for var_name in variables_mapping:
 
-            var_value = variables_mapping[var_name]
-            # variables = extract_variables(var_value)
-
             if var_name in parsed_variables:
                 continue
 
-            parsed_value = parse_content(var_value, parsed_variables)
+            var_value = variables_mapping[var_name]
+            # variables = extract_variables(var_value)
+
+            try:
+                parsed_value = parse_content(var_value, parsed_variables)
+            except VariableNotFound:
+                continue
+
             parsed_variables[var_name] = parsed_value
 
     return parsed_variables
diff --git a/httprunner/v3/runner.py b/httprunner/v3/runner.py
index fc237f71..12d28059 100644
--- a/httprunner/v3/runner.py
+++ b/httprunner/v3/runner.py
@@ -3,7 +3,7 @@ from typing import List
 import requests
 from loguru import logger
 
-from httprunner.v3.parser import build_url, parse_content
+from httprunner.v3.parser import build_url, parse_content, parse_variables_mapping
 from httprunner.v3.response import ResponseObject
 from httprunner.v3.schema import TestsConfig, TestStep
 
@@ -57,9 +57,15 @@ class TestCaseRunner(object):
         """main entrance"""
         session_variables = {}
         for step in self.teststeps:
+            # update with config variables
             step.variables.update(self.config.variables)
+            # update with session variables extracted from former step
             step.variables.update(session_variables)
+            # parse variables
+            step.variables = parse_variables_mapping(step.variables)
+            # run step
             extract_mapping = self.run_step(step)
+            # save extracted variables to session variables
             session_variables.update(extract_mapping)
 
     def run(self):