Abstract: Timely and comprehensive grasp of the operation status information and fault information of EMU is an important method to improve the operation and maintenance level of EMU. It can detect the operation state in real time and effectively ensure the operation safety of EMU by using the vehicle ground communication. The use of non real time onboard data of EMU can effectively enhance maintenance capability and improve the maintenance level of EMU. This article introduced the development status of EMU onboard information system, studied on the overall architecture of the system, main functions and key technologies, put forward some suggestions on the construction of integrated application system for EMU onboard information.