Plastic injecting mold is widest applicated in manufacturing industries as it can form complex and high precision plastic production. The paper has introduced the plastic injecting mold’s position and function in the manufacturing process of the modern society , and analysised the structure of the plastic product . The paper introduced the concrete process of the plastic mold’s designing. The next chapter introduced the concrete design process of the plastic injecting mold. The injecting machine was chosen according to the product’s weight, the face was chosen according to the structure of the plastics and model the type of cent of the craft、taking out the organization of core and the outing organizations、noting system、cooling system and resetting the system to carry on the detailed design towards modeling parts and sprinkling at the same time.In addition, some design had been carried on the other parts of the plastic injecting mold. The insight was elaborated in the end of the paper, and I had put forward my own views and viewpoints, too.