Aiming at loading and unloading of work pieces on the automatic production lines, designs the gear type mechanical structure of the manipulator wrist and execution hand claw. Adopts the hydraulic control system to control three actuators’ movement of the manipulator, including the vertical hydraulic cylinder for the vertical arm rise and fall, the horizontal telescopic hydraulic cylinder for the wrist stretch forward and backward retraction and the plunger hydraulic cylinder for the gripper clamping and open. Through analysis and calculation of the mechanical properties of the manipulator, proves that the manipulator device is simple and reliable, and has the ability to grip and handle 30 kg workpiece. The design of PLC control system enables the manipulator to realize the functional requirements of automatic workpieces loading and unloading on production line.