The invention relates to a robot claw, which comprises a cylinder body, a bidirectional cylinder, a positioning dowel and grabbing nippers. The bidirectional cylinder is arranged on the cylinder body, two spindle pistons are respectively disposed at two ends of the bidirectional cylinder, the grabbing nippers are disposed on the spindle pistons, the positioning dowel is arranged on the lower surface of the cylinder body, jacking mechanisms are arranged on the grabbing nippers, each jacking mechanism consists of a jacking cylinder and a jacking rod, and each jacking rod is disposed on the corresponding jacking cylinder. When a robot induces that the weight of a grabbed article exceeds rated load of the robot, a control system of the robot transmits a signal to the jacking mechanisms of the robot claw, the jacking cylinders of the jacking mechanisms on two sides of the robot claw act simultaneously, a positioning hole of the grabbed article is released from the positioning dowel of a machining cabinet by the aid of matching of the robot, and accordingly a jig or the grabbed article is stably and vertically released from the positioning dowel on the machining cabinet. In addition, the jacking mechanisms are disposed on the grabbing nippers, accordingly, a space is saved better, and the weight is lightened better.