In the signal system of urban rail transit, in order to ensure the safety of train services, ZC estimates the occupation position of non-communication train at the cost of accuracy after the train running in CBTC level is degraded, it takes the axle counter as the unit to judge the occupation position of non-communication train, and takes the idle axle counter on both sides of the occupied axle counter as the possible occupation range of non-communication train. This paper improves the scheme and proposes a new method to judge the train occupation position based on the integration of ZC and CI equipment. It realizes the fine management of the train occupation position and improves the accuracy of the train occupation position, so it can meet the application requirements of the line with smaller interval and higher speed under the CBTC mixed running mode. At the same time, it can improve the accuracy of judging the failure of axle counter equipment. In brief, this paper has some reference value for improving the reliability and availability of CBTC system.