The paper finished the design of injection molding by UG MoldWizard module, and realized numerical simulation and analysis of injection process by MoldFlow software. Best gate location was obtained. Fill time was deeply studied. Though the mold designing process, it completed the CAD/CAM/CAE integration of the injection molding, and achieved the optimal design of the mold. NC machining of the mold core was programmed by UG NX software. CAD/CAM/CAE greatly improved the development efficient of the mold.