The invention discloses a workpiece positioning device. The device comprises a frame, a clamping plate for supporting a workpiece to be processed is arranged above the frame, a baffle is arranged at the front end of the clamping plate, and the baffle is used for limiting the front end of the workpiece to be processed. A sensor is mounted on the baffle, and the sensor is used for sensing the position of the workpiece to be processed. The rear end of the clamping plate is provided with a poking plate capable of moving in the axial direction of the clamping plate, and the poking plate is connected with a driving mechanism. According to the device, after the workpiece to be processed is placed on the clamping plate, the poking plate can push the workpiece to be processed from the back to the front under driving of the driving mechanism till the front end of the workpiece to be processed contacts the baffle and can no longer move, and the sensor can sense the position of the workpiece to beprocessed. At the same time, the position information of the workpiece to be processed can be sent to an external manipulator, and the manipulator can pick up the workpiece to a clamping mechanism ofan external drilling machine when learning that the workpiece to be processed is pushed to the correct position. No manual operation of workers is required, and production safety can be ensured.