The AVN2440DS shield machine consists of cutterhead driving system, thrust system, guidance system, segment erection system, grease injection system, main bearing lubrication system, slurry feed and return system, simultaneous grouting system, segment delivery and hoisting system and backup gantries. All the functions of the shield machine are controlled at the control panel by the operators through various control systems. Furthermore, the shield machine is equipped with the protection devices for the electricity systems and hydraulic systems respectively, so as to ensure the normal working of the complete shield machine. On basis of the experience gained in the processing of the common electric failures of the AVN2440DS shield machine in Chenglingji Yangtze River crossing tunnel and Qianwan subsea tunnel in Shenzhen, the article expatiates on the analysis on and processing of the switch tripping of the major electricity loops, which is one of the common electric failures of the mentioned slurry shield machine.