diff --git a/weixin/mp_sdk.go b/weixin/mp_sdk.go
index 3cc7876..f8fb5f8 100644
--- a/weixin/mp_sdk.go
+++ b/weixin/mp_sdk.go
@@ -111,22 +111,23 @@ func (o *MpSdk) GetUnlimitedQRCode(params map[string]interface{}) ([]byte, error
 
 func (o *MpSdk) GetScheme(params map[string]interface{}) (string, error) {
 
+	newParams := make(map[string]interface{})
+	jump_wxa := make(map[string]interface{})
 	if _, ok := params["env_version"]; !ok {
-		params["env_version"] = "release"
+		jump_wxa["env_version"] = "release"
+	} else {
+		jump_wxa["env_version"] = cast.ToString(params["env_version"])
 	}
 
-	jump_wxa := make(map[string]interface{})
-
-	jump_wxa["env_version"] = params["env_version"]
 	jump_wxa["path"] = params["path"]
 	jump_wxa["query"] = params["query"]
-	params["jump_wxa"] = jump_wxa
+	newParams["jump_wxa"] = jump_wxa
 
-	params["expire_interval"] = 30
-	params["expire_type"] = 1
-	params["is_expire"] = true
+	newParams["expire_interval"] = 30
+	newParams["expire_type"] = 1
+	newParams["is_expire"] = true
 
-	marshal, _ := json.Marshal(params)
+	marshal, _ := json.Marshal(newParams)
 	accessToken, err := o.getAccessToken()
 	if err != nil {
 		return "", err