The utility model relates to a transfer files blocking device of circuit of capacitor bank belongs to the electrical technology field. The device concatenates between power supply circuit and capacitor bank to by the main road, be used for shift up's first branch road and the second branch road that is used for lowering category is constituteed, first branch road is parallelly connected with the second branch road, and the main road is established ties with parallel circuit in proper order, the main road is established ties in proper order by tripping operation circuit and locking circuit and is formed, when the disconnection of tripping operation circuit, capacitor bank was electrified this moment, and this return circuit is in the tripping operation state, as tripping operation circuit conduction, the locking circuit disconnection, capacitor bank was not electrified this moment, and this return circuit is in blocking state, as tripping operation circuit conduction, shutting circuit conduction, this return circuit is in operating condition, and capacitor bank was not electrified this moment, and capacitor bank's gear is adjusted to first branch road of accessible or second branch road. The device is through tripping operation and locking circuit's cooperation to it is electrified to guarantee that capacitor bank transfers the files the in -process, improves capacitor bank the transfer the files reliability and the real -time of operation.