Abstract: According to the control principle of escape door, the strategy and specific implementation method of escape door function detection and fault diagnosis are described. Before the FAO (fully automatic operation) train is launched for operation on main line, through software logic control of train control and diagnosis system, the escape door is forced to complete once locking and opening function test. The zerospeed signal is bypassed by the action of escape door detection pulse signal through hardwired circuit design to distinguish between the opening and fault states of the escape door. Based on the feedback of escape door electromagnetic lock state, the escape door function detection and fault diagnosis are realized. Simulation test results show that the function detection of the escape door can improve its functions，ensure its availability and reliability in train fully automatic operation.