Abstract: The FAO (fully automatic operation) system represents the future development trend of urban rail transit. According to the FAO construction requirements of Guangzhou Metro Line 7 west extension and phase II engineering, combined with the existing technology and equipment level of Line 7, by exploring schemes such as the upgrading and installation of key equipment of existing signaling system, the interface between on-board signal equipment and vehicle, the overall technical scheme of the FAO system is designed. A minimized FAO system is constructed, and high-level FAO function is realized. All key technologies of the FAO system are verified to meet the FAO requirements.