diff --git a/examples/extract_test.go b/examples/extract_test.go
new file mode 100644
index 00000000..1fb1df8c
--- /dev/null
+++ b/examples/extract_test.go
@@ -0,0 +1,44 @@
+package postman_echo
+
+import (
+	"testing"
+
+	"github.com/httprunner/httpboomer"
+)
+
+func TestCaseExtractStep(t *testing.T) {
+	testcase := &httpboomer.TestCase{
+		Config: httpboomer.TConfig{
+			Name:    "run request with variables",
+			BaseURL: "https://postman-echo.com",
+			Verify:  false,
+		},
+		TestSteps: []httpboomer.IStep{
+			httpboomer.Step("get with params").
+				WithVariables(map[string]interface{}{
+					"var1":               "bar1",
+					"agent":              "HttpBoomer",
+					"expectedStatusCode": 200,
+				}).
+				GET("/get").
+				WithParams(map[string]interface{}{"foo1": "$var1", "foo2": "bar2"}).
+				WithHeaders(map[string]string{"User-Agent": "$agent"}).
+				Extract().
+				WithJmesPath("status_code", "statusCode").
+				WithJmesPath("headers.\"Content-Type\"", "contentType").
+				WithJmesPath("body.args.foo1", "varFoo1").
+				Validate().
+				AssertEqual("$statusCode", "$expectedStatusCode", "check status code"). // assert with extracted variable
+				AssertEqual("headers.Connection", "keep-alive", "check header Connection").
+				AssertEqual("$contentType", "application/json; charset=utf-8", "check header Content-Type"). // assert with extracted variable
+				AssertEqual("$varFoo1", "bar1", "check args foo1").                                          // assert with extracted variable
+				AssertEqual("body.args.foo2", "bar2", "check args foo2").
+				AssertEqual("body.headers.\"user-agent\"", "HttpBoomer", "check header user agent"),
+		},
+	}
+
+	err := httpboomer.Test(t, testcase)
+	if err != nil {
+		t.Fatalf("run testcase error: %v", err)
+	}
+}
diff --git a/response.go b/response.go
index bcd18d10..a61abc92 100644
--- a/response.go
+++ b/response.go
@@ -3,6 +3,7 @@ package httpboomer
 import (
 	"encoding/json"
 	"log"
+	"strings"
 	"testing"
 
 	"github.com/imroc/req"
@@ -99,12 +100,21 @@ func (v *ResponseObject) Validate(validators []TValidator, variablesMapping map[
 	for _, validator := range validators {
 		// parse check value
 		checkItem := validator.Check
-		checkValue := v.searchJmespath(checkItem)
+		var checkValue interface{}
+		if strings.Contains(checkItem, "$") {
+			// reference variable
+			checkValue = parseData(checkItem, variablesMapping)
+		} else {
+			checkValue = v.searchJmespath(checkItem)
+		}
+
 		// get assert method
 		assertMethod := validator.Assert
 		assertFunc := assertFunctionsMap[assertMethod]
+
 		// parse expected value
 		expectValue := parseData(validator.Expect, variablesMapping)
+
 		// do assertion
 		result := assertFunc(v.t, expectValue, checkValue)
 		log.Printf("assert %s %s %v => %v", checkItem, assertMethod, expectValue, result)
@@ -119,7 +129,7 @@ func (v *ResponseObject) searchJmespath(expr string) interface{} {
 	checkValue, err := jmespath.Search(expr, v.respObjMeta)
 	if err != nil {
 		log.Printf("[searchJmespath] jmespath.Search error: %v", err)
-		return nil
+		return expr // jmespath not found, return the expression
 	}
 	return checkValue
 }