Abstract: The vehicle door lifespan is analyzed according to EMU (electric multiple units) compartment door system fault data, a conclusion that the fault interval conforms to Weibull distribution is obtained. Under the condition that vehicle door system reliability meets operation requirements, a maintenance model aiming at the lowest maintenance cost per unit time is established. With the mentioned maintenance model, maintenance cycle of China Railway Shanghai Bureau Group CRH2A EMU compartment door system is optimized. The practicability and economy of the optimized maintenance model is verified.