Abstract: Process design and numerical simulation of the turbine nozzle were carried out with the help of ProCAST software, and potential problems and causes of defects in the filling and solidification process were analyzed in detail.On this basis, the process was optimized by adjusting the pouring method, riser quantities and size, and casting solidification order, and numerical simulation was carried out. The results demonstrate that the filling process of the optimized process is stable, the casting can sequentially solidify without defects, and the metal utilization rate is increased from 12.13% to 43.18%. The optimization process is verified by the actual casting, the casting quality meets the requirements of specification EMS52301/2.