The graduation design subject to cover the injection molding design, mainly from the plastic material characteristics, forming performance and plastic parts, die-cavity structure is analyzed in detail from multiple perspectives, such as plastic injection molding process technology. Because there is no batch production requirements, and small parts, simple structure, a mold piece of the means of production. Preliminary selection of type and specification, injection molded parts structure analysis and production mode, appropriate USES double type structure, gating system, forming parts, orientation and positioning and demoulding mechanism, cooling system, formwork components parts are made of calculation and choice. Finally, in the reference of the volume, weight after injection parameters such as the main parameters related to test to determine whether meet the selected injection molding requirements.