Abstract: The practical application requirements of automatic fare collection (AFC) system for rail transit under the new situation are expounded. By analyzing the problems in traditional AFC system architecture and the actual optimization application in Chinese cities based on the traditional architecture, an architecture of rail transit AFC system based on dual active architecture is proposed, the system function of ACLC (adaptive communication line controller) and the switching of abnormal scenarios in the dual active architecture are analyzed. Finally, the key technologies of AFC system dual active architecture, such as load balancing technology, distributed cache cluster technology, data synchronization technology and cloud platform technology are analyzed emphatically.