The working condition of the plastic injection mold were analyzed,proposed that design the plastic parts and the injection mold with reasonable,can guarantee the structure of the inject mold become more reasonable.Selected the mold material and the heat treatment method with reasonable,can guarantee the operation requirements of inject mold;optimized the fabrication technology,can guarantee the manufacture quality of the inject mold;Intensified surface,can enhances the surface quality of the injection mold work components;Used and maintained correctly,can optimize the working condition of inject mold;The service life of the plastic inject mold were enhanced through the methods that presented above.