The invention provides a mechanical part cleaning device, and relates to the field of mechanical part cleaning. The mechanical part cleaning device comprises a cleaning box, a water inlet pipe, a mounting frame, a driving motor and a cover plate, the mounting frame is arranged on the outer wall of one side of the cleaning box, the cover plate is hinged to the outer wall of one side of the cleaning box, the driving motor is arranged on the outer wall of the bottom end of the cleaning box, the output of the driving motor is connected with a rotating shaft through a coupler, a protection plate is arranged on the outer wall of the rotating shaft, a supporting plate is arranged on the outer wall of the top end of the protection plate, a rotating mechanism is arranged outside one end of the rotating shaft, a cleaning cylinder is arranged on the outer wall of one side of the supporting plate, and a polygonal plate is arranged on the inner wall of the cleaning box. According to the mechanical part cleaning device, the impact force of water flow on parts is intensified, so that the cleaning effect is enhanced, impurities on the parts can rapidly fall off, mutual collision between the parts in the cleaning process can be reduced, and the parts are protected in the cleaning process.