Abstract: At present, the signaling system that accommodates both CTCS (China train control system) and CBTC (communication based train control) is under development. Whether the signaling system can realize interoperation has become the top priority for train mixed operation on rail transit lines with different signal systems under multi-network integration. Taking CTCS and CBTC as the research objects, the technical characteristics and compatible feasibility of both are analyzed, the possibilities of various selection schemes for city railway train control signaling system are studied. Targeting the signaling formats of CBTC and CTCS, the double on-board equipment and the integrated on-board equipment are recommended, the advantages and disadvantages of the two schemes are analyzed respectively, so as to provide reference for the interoperability design of city railway signaling system under multinetwork integration.