Abstract: Taking an impeller made of Al-Si Alloy ZAlSi9Cu2Mg as the research object, the casting process scheme of ZL111 impeller was designed and optimized by combining casting process design optimization and numerical simulation.According to its structural characteristics, the gating system was designed, and the resin sand molding core making and hot box sand casting process were selected.After determining the gating system, AnyCasting software was used to simulate the filling and solidification process of the casting, and the location of defects in the impeller casting was predicted.It was found that the filling process of the impeller was stable, and shrinkage porosity and shrinkage cavity appeared in the center of the impeller.Through the analysis of the causes of the defects, the casting process plan was optimized and improved.Finally, through simulation, it is found that the defects of impeller casting can be eliminated by placing chill iron, which provides a reasonable and feasible casting process scheme for large batch of medium-sized casting ZL111 impeller, which plays a guiding role in the actual production, so as to ensure the quality of impeller products.