Based on the traditional train ground communication, the train control system introduces the train ground communication technology to realize the real-time communication between the rear train and the front train, which greatly simplifies the ground equipment and improves the train operation efficiency. This paper used STPA method to analysis the security ofresource management unit, the key equipment of the system. The process of Temporary Speed Restriction sending by RMU is studied as typical of the control scenario. The dangerous behaviors in the process are identified, the unsafe factors of the system are found out, and SDR is formulated in the scenario. The timed automata network model of TSR sending scenario is built by SDR condition, and UPPAAL is used to verify the model. The verification shows that STPa method can find the control defects in the train control system, and adopt corresponding strategies to improve the security of the system, which has good applicability in the security analysis of the train control system.