A battery replacement system for secondary side equipment of a power system includes a shell, a battery carrier and an actuator. The battery carrier is cylindrical, a cylindrical groove matched with the battery carrier is arranged on the shell, and the battery carrier is mounted in the cylindrical groove; The shell is provided with a cavity connecting the inside of the cylindrical groove and the outside of the shell; and the actuator is arranged in the cavity. According to the battery replacement system for secondary side equipment of a power system, through the abovementioned components, theeffect is achieved that in replacement ofa lead-acid battery of the power system, the turn-off time is very short, the safety of power system operation is greatly improved, and the cost of manpower and material resources is reduced.