Abstract: In order to promote the efficient integration and regional integration of rail transit networks, this study takes the compatibility of CBTC system and CTCS as the research object to explore the key path of rail transit control system interconnection. It aims to solve problems such as insufficient synergy under different systems, optimize the travel experience through technological innovation, and support the implementation of national regional strategies. From the perspective of systematics, the interconnection level is divided, the interconnection framework is defined from three elements: technical elements, semantic elements and application scenarios, and the nine design principles of system interconnection are summarized. Taking CTCS (such as CTCS-2level) and CBTC system as examples, on the basis of differentiated analysis from three aspects of system architecture, function and control mode, two design schemes of horizontal integration and vertical integration are proposed, and the two schemes are compared and analyzed, which provides reference and reference for the interconnection of rail transit and other systems.