diff --git a/zh-cn/application-dev/ability/service-ability.md b/zh-cn/application-dev/ability/service-ability.md
index 908875bb4216b7aadcf4cfd796a4a57680bb05ac..8a1fba4b41c7792ad617da9e36bb060235334e4d 100644
--- a/zh-cn/application-dev/ability/service-ability.md
+++ b/zh-cn/application-dev/ability/service-ability.md
@@ -157,10 +157,7 @@ export default {
     onStart(want) {
         class MyStub extends rpc.RemoteObject{
             constructor(des) {
-                if (typeof des === 'string') {
-                    super(des, des.length);
-                }
-                return null;
+                    super(des);
             }
             onRemoteRequest(code, message, reply, option) {
             }