In order to accurately evaluate the radiation dose distribution around the radioactive equipment in nuclear power plants, this study used the three-dimensional radiation dose field fast calculation software (DOLPHINS) to simulate typical nuclear power plant equipment. Based on the Monte Carlo method, this software can quickly and efficiently simulate radiation sources of different shapes and materials, and calculate their radiation dose distribution in three-dimensional space. The study selected pipes, pumps, valves and other equipment in typical nuclear power plants, and established their three-dimensional geometric models. By inputting the material information, radionuclide information, source intensity information and simulation parameters of the equipment, the DOLPHINS software simulated the radiation dose distribution around the equipment under different working conditions, and compared it with the traditional dose calculation method. The results show that the DOLPHINS software can quickly and accurately simulate the radiation dose distribution around the equipment, and its calculation results are consistent with the traditional method, and the simulation efficiency is higher, which can effectively reduce the workload of manual calculation. This study can provide a reference for the radiation protection design, dose assessment and personnel radiation protection of nuclear power plant equipment.