Using Moldflow software to analyze and optimize the mold flow of a automotive front bumper, combined with simulation analysis results and the structural characteristics of the plastic parts, an 8-point needle valve gating system was designed to achieve equal velocity of the melt flow front and achieve balanced mold filling. In order to solve the problem of plastic parts being pulled and stuck to the fixed mold cavity after mold opening caused by multiple front rib positions of the product, an innovative anti plastic part sticking fixed mold mechanism with "bent pin+movable pressure block+reset rod" was designed. The mechanical core pulling mechanism of "large inclined top+push block+T-shaped block+movable pull rod" has successfully solved the problem of small space and difficult demolding of the reverse buckle core pulling at both ends of the plastic part. The core pulling mechanism of "spring block+guide rod+nitrogen spring" solved the problem of plastic fixed mold reverse buckle demolding. The problem of adjusting the imbalance of large molds installed in injection molding machines has been solved by designing a "gear+balance block" mechanism. Adopting a combined cooling water circuit structure, the mold temperature was uniform. A combined demolding mechanism that can be ejected in two stages was designed, with high efficiency and safety reliability. After production verification, the mold runs smoothly and the dimensions of the plastic parts met the accuracy requirements.