The nuclear power valve is an important piece of equipment in any nuclear power system. The finite element method was used in this study to analyze the strength and rigidity of the high-temperature and high-pressure nuclear gate valve. The structural characteristics were optimized as per the parameters that affect the strength of the valve body. Fluid-solid coupling technology was utilized to investigate the temperature, deformation, and stress distributions in the structure. A high stress concentration was observed in the initial design; the maximum equivalent stress exceeded the allowable range. Three optimization methods were deployed in efforts to improve the stress distribution. The stress distribution was found to be more uniform post-optimization and the gate valve structure of all three schemes tested met the relevant stress requirements. The optimal scheme was then determined by further comparison. The results presented here may provide a theoretical reference for the optimization of nuclear power valve designs.