Abstract: The data communication between the automatic train monitoring (ATS) and the vehicle on-board controller (VOBC) is in open network environment, which has higher requirement on the reliability and timeless of communication between devices. To satisfy the performance of communication, this article combined with the railway signal safety communication protocol(RSSP-II), discussed the communication framework between ATS and VOBC, designed and implemented communication interface module for ATS and VOBC. The communication module was tested and verified by the ATS simulation platform.