The new on-board control and diagnosis system component is an important unit equipment in the on-board control and diagnosis system of high-speed maglev narrow vehicle body. Its function is to send the safety related control instructions from the on-board safety computer to the vehicle subsystem, and feed back the status monitoring signal sent by the subsystem to the on-board safety computer. In order to ensure the safe and reliable operation of the control and diagnosis system, the components of the new on-board control and diagnosis system adopt redundant architecture and modular design to form a dual redundant architecture, which makes the equipment highly stable and simplifies the circuit design. It can also carry out logic function debugging and fault diagnosis through programming and diagnosis software.