Considering the importance of traction power supply system in urban rail transit, it is difficult to carry out prognostic and health management (PHM) experiments in traction power supply system. Therefore, a simulation platform of traction power supply system is constructed in this paper. The platform simulates various operating conditions and fault states of the traction power supply system by building a physical model of the traction power supply system of low-power rail transit. This paper mainly introduces the main structure and system design of the dynamic simulation platform, and by using the upper computer monitoring software to realize the function of vehicle-ground wireless communication, the train group in the system can run under different working conditions.