Abstract: HMI (Human Machine Interface) is the display terminal of the TCMS system, and it is an important platform for drivers and maintenance personnel to monitor the running status of trains. It can realize functions of train running status monitoring, fault diagnosis and alarm, data configuration and vehicle control, therefore HMI is a key component ensuring the safety of train operation, and multi\|redundancy design of EMU HMI is evidently significant. The design and implementation of the multi\|redundancy function of train HMI based on Ethernet bidirectional loop communication are introduced, including redundancy design of hardware equipment, vehicle topology, and HMI software control strategy. Redundancy design of full aspects can effectively ensure the safety of train operation, as well as reduce maintenance costs, and improve the reliability of train operation.