Abstract: In order to improve the product quality of the aluminum alloy hollow control arm, the differential pressure casting process was analyzed by numerical simulation. The possible shrinkage and porosity defects were predicted by analyzing the change of solid phase ratio during the solidification process of the casting. The forming process was optimized by cooling optimization and Box-Behnken method in response surface method. Genetic algorithm was applied to obtain the optimal process parameter combination, and metallographic analysis was applied to further verify the optimization results. The results show that when the cooling water temperature is 53 ℃, the flow rate of cooling water is 2.9 m³/h, the pouring temperature is 707 ℃ and the mold preheating temperature is 321 ℃, there is no obvious porosity defect in the casting, and the mechanical properties of the casting are good.