diff --git a/hrp/step_api.go b/hrp/step_api.go
index cce14cd0..a2c0bad0 100644
--- a/hrp/step_api.go
+++ b/hrp/step_api.go
@@ -117,6 +117,10 @@ func extendWithAPI(testStep *TStep, overriddenStep *API) {
 	}
 	// merge & override request
 	testStep.Request = overriddenStep.Request
+	// init upload
+	if testStep.Request.Upload != nil {
+		initUpload(testStep)
+	}
 	// merge & override variables
 	testStep.Variables = mergeVariables(testStep.Variables, overriddenStep.Variables)
 	// merge & override extractors
diff --git a/hrp/step_request.go b/hrp/step_request.go
index 29a86578..a854af19 100644
--- a/hrp/step_request.go
+++ b/hrp/step_request.go
@@ -259,24 +259,31 @@ func (r *requestBuilder) prepareBody(stepVariables map[string]interface{}) error
 	return nil
 }
 
-func prepareUpload(parser *Parser, step *TStep) (err error) {
-	if step.Request.Upload == nil {
-		return
-	}
-	step.Request.Upload, err = parser.ParseVariables(step.Request.Upload)
-	if err != nil {
-		return
-	}
-	if step.Variables == nil {
-		step.Variables = make(map[string]interface{})
-	}
-	step.Variables["m_upload"] = step.Request.Upload
-	step.Variables["m_encoder"] = fmt.Sprintf("${multipart_encoder($m_upload)}")
+func initUpload(step *TStep) {
 	if step.Request.Headers == nil {
 		step.Request.Headers = make(map[string]string)
 	}
 	step.Request.Headers["Content-Type"] = "${multipart_content_type($m_encoder)}"
 	step.Request.Body = "$m_encoder"
+}
+
+func prepareUpload(parser *Parser, step *TStep, stepVariables map[string]interface{}) (err error) {
+	if step.Request.Upload == nil {
+		return
+	}
+	uploadSlice := map[string]interface{}{}
+	for key, value := range step.Request.Upload {
+		uploadSlice[key], err = parser.Parse(value, stepVariables)
+		if err != nil {
+			return
+		}
+	}
+	stepVariables["m_upload"] = uploadSlice
+	mEncoder, err := parser.Parse("${multipart_encoder($m_upload)}", stepVariables)
+	if err != nil {
+		return
+	}
+	stepVariables["m_encoder"] = mEncoder
 	return
 }
 
@@ -295,13 +302,13 @@ func runStepRequest(r *SessionRunner, step *TStep) (stepResult *StepResult, err
 		}
 	}()
 
-	err = prepareUpload(r.parser, step)
+	// override step variables
+	stepVariables, err := r.MergeStepVariables(step.Variables)
 	if err != nil {
 		return
 	}
 
-	// override step variables
-	stepVariables, err := r.MergeStepVariables(step.Variables)
+	err = prepareUpload(r.parser, step, stepVariables)
 	if err != nil {
 		return
 	}
@@ -822,6 +829,8 @@ func (s *StepRequestWithOptionalArgs) WithBody(body interface{}) *StepRequestWit
 
 // WithUpload sets HTTP request body for uploading file(s).
 func (s *StepRequestWithOptionalArgs) WithUpload(upload map[string]interface{}) *StepRequestWithOptionalArgs {
+	// init upload
+	initUpload(s.step)
 	s.step.Request.Upload = upload
 	return s
 }
diff --git a/hrp/testcase.go b/hrp/testcase.go
index 6a91939b..69120497 100644
--- a/hrp/testcase.go
+++ b/hrp/testcase.go
@@ -144,6 +144,10 @@ func (path *TestCasePath) ToTestCase() (*TestCase, error) {
 				step: step,
 			})
 		} else if step.Request != nil {
+			// init upload
+			if step.Request.Upload != nil {
+				initUpload(step)
+			}
 			testCase.TestSteps = append(testCase.TestSteps, &StepRequestWithOptionalArgs{
 				step: step,
 			})
diff --git a/hrp/tests/upload_test.go b/hrp/tests/upload_test.go
index d9273d17..2897eabe 100644
--- a/hrp/tests/upload_test.go
+++ b/hrp/tests/upload_test.go
@@ -9,12 +9,13 @@ import (
 func TestCaseUploadFile(t *testing.T) {
 	testcase := &hrp.TestCase{
 		Config: hrp.NewConfig("test upload file to httpbin").
-			SetBaseURL("https://httpbin.org"),
+			SetBaseURL("https://httpbin.org").
+			WithVariables(map[string]interface{}{"upload_file": "test.env"}),
 		TestSteps: []hrp.IStep{
 			hrp.NewStep("upload file").
 				WithVariables(map[string]interface{}{
 					"m_encoder": "${multipart_encoder($m_upload)}",
-					"m_upload":  map[string]interface{}{"file": "test.env"},
+					"m_upload":  map[string]interface{}{"file": "$upload_file"},
 				}).
 				POST("/post").
 				WithHeaders(map[string]string{"Content-Type": "${multipart_content_type($m_encoder)}"}).
@@ -24,7 +25,7 @@ func TestCaseUploadFile(t *testing.T) {
 				AssertStartsWith("body.files.file", "UserName=test", "check uploaded file"),
 			hrp.NewStep("upload file with keyword").
 				POST("/post").
-				WithUpload(map[string]interface{}{"file": "test.env"}).
+				WithUpload(map[string]interface{}{"file": "$upload_file"}).
 				Validate().
 				AssertEqual("status_code", 200, "check status code").
 				AssertStartsWith("body.files.file", "UserName=test", "check uploaded file"),