The polishing method is as follows: the better the surface smoothness of plastic electroplated plastic parts, the better the appearance after electroplating. In general, injection-molded products can also meet the requirements of electroplating process, and the plastic surface can be directly electroplated without defects. However, due to the limitation of production conditions, plastic electroplating injection molding can not meet the requirements before electroplating. For example, the surface roughness, fog surface, frost surface, adhesive line, mold mark, waterline, burrs and burrs of injection molded parts will inevitably scratch the appearance of some products. At this time, it is necessary to polish the surface of plastic parts to eliminate surface defects and make the plastic surface smooth and high gloss.