Abstract: Based on the analysis of the safety problems of train door and platform door in rail transit under different control time sequences, this paper proposed the switching action time sequence scheme of train door and platform door. Through the logical analysis of the control mode of the existing platform door system and the interface conditions between the platform door and the train control center, the paper proposed the functional design scheme of the time delay control system, and described the interface principle and work flow in detail. The system was composed of safety relay and central logic processing unit, with the principle of “fault oriented safety”, had a complete self-test function. The system function was verified in the laboratory environment. By simulating the control command of the train control center, the system could accurately delay, record and deal with the fault to the control command. The test results show that the system is simple, practical, safe and reliable, which improves the safety and comfort of passengers, and plays an important role in upgrading the existing station platform door system.