Abstract: The passenger service system under the fully automatic operation mode of urban rail transit implemented the functions of real-time collection of equipment status information, and analysis of on-board equipment status, fault alarm and etc., through passenger two-way intercom, emergency linkage response and real-time monitoring of on-board equipment status, so as to improve the overall efficiency of operation, disaster relief emergency level and intelligent application level. This article introduced the key technologies of passenger service system under the fully automatic operation mode. The application in Yanfang Line of Beijing Metro and Daxing Airport Line of Beijing Metro showed that these technologies could meet the application scenarios and requirements of full-automatic operation.