The utility model provides a robot gripper. The robot gripper is connected to the robot arm. The grabbing device comprises a grabbing piece and an air cylinder, the air cylinder is provided with a first finger and a second finger which can move, a plunger of the air cylinder moves to drive the first finger and the second finger to change the distance, the grabbing piece comprises a first grabbingclaw and a second grabbing claw, the first grabbing claw is fixedly connected to the first finger, and the second grabbing claw is fixedly connected to the second finger. According to the robot gripper provided by the utility model, a circuit breaker can be firmly fixed on the robot gripper in the grabbing, moving and mounting processes of a robot, the purpose of replacing manual grabbing of the circuit breaker by the robot is achieved, the mounting operation efficiency of the circuit breaker is improved, meanwhile, the high error rate of manual operation can be reduced, and the labor intensity of workers is reduced.