Hi Zhang,
If you are looking to integrate your UI5 application into the Fiori Launchpad then your project must be based on a component (Component.js). There is no need for index.html in your project if you are not going to run your app as a stand alone app. index.html is needed only to run the app in stand alone mode.
The newer Fiori apps are based on the Component.js file and do not run the index.html file when accessed through the launchpad.
Regards,
Saurabh