The planetary carrier is the key transmission component that bears torque and dynamic load in the gear transmission system of the shearer. In recent years, it has often been scrapped due to multiple cracks, which are directly related to casting defects. Based on this, a reasonable casting process plan is proposed for the planetary carrier used for the gear transmission of the shearer. Using ProCAST software, the simulation results of the temperature field, velocity field, solidification solid rate and shrinkage cavity distribution of planetary carrier casting during mold filling and solidification were studied, and the casting scheme was optimized according to the simulation results. The results show that after the addition of open risers and cold iron, the shrinkage porosity and other defects of the planet carrier are effectively controlled, the partial defects of the side plate of the planet carrier are reduced by more than 57%, and cylindrical defects are completely avoided. The casting simulation effectively guides the prevention and treatment of shrinkage porosity defects of planetary carriers used for coal engine gear transmission and fundamentally solves the problem of multiple cracks.