Abstract: Train Communication Network (TCN) provides public communications for EMU train operation control, multi-train coupling control, vehicle maintenance and passenger service, and realizes train information transmission and sharing. China's existing EMU TCN adopts the technology of WTB (Wire Train Bus) + MVB (Multifunction Vehicle Bus) based on IEC 61375 standard. It is difficult to meet the increasing demand for train data transmission in the process of technology upgrading due to limited data transmission bandwidth and lack of redundance in part of communication lines. To deal with various data transmission requirements of EMU TCN, industrial Ethernet is applied to EMU's train communication network to replace and upgrade the existing EMU's TCN technology. The test results show that using the EMU Ethernet designed in this paper as the train communication network, the communication status and communication quality test results of all subsystems of the EMU can meet the evaluation standards, meet the train control and management requirements, and the system runs stably and meets the design requirements. The EMU Ethernet designed in this paper has been widely used in Fuxing series EMU and intercity and urban rail vehicles in Shanghai, Guiyang and other cities, with high data transmission rate, strong stability and convenient equipment maintenance, which is conducive to rapidly improving the levels of vehicle maintenance and passenger service of rail trains.