Abstract: In this paper, SolidWorks software was used to create the 3D model of gray iron upper rotary disc casting. Based on the analysis of the structure, shape, size and practical application of the upper rotary disc casting,the casting process scheme of the gray iron casting was initially designed, and ProCAST software was used for numerical simulation and analysis. According to the simulation results of defects distribution during casting, the casting process was adjusted by adding risers and optimizing the pouring system. After optimization and simulation,the shrinkage and porosity defects are effectively controlled.