With the construction of large-capacity pumped storage power plants, the problem of transformer winding overheating become more prominent. Given the technical shortage of the real-time monitoring for hot spot temperature of oil-immersed transformers in pumped storage power plants, taking a large oil-immersed transformer as the research object, and the finite element and heat transfer principle are taken as theoretical basis, a hot spot temperature simulation analysis method based on temperature field distribution calculation is proposed in this paper. A magneto-thermal coupling finite element simulation is carried out. The winding structure and oil flow conditions are simplified, and the simulation parameters are set based on existing technical parameters and monitoring data. The temperature field distribution results meeting engineering requirements are calculated, so that the hot spot temperature is obtained. The rationality and accuracy of the temperature field distribution calculation are verified by comparing the monitoring data, the standard model calculation results and the simulation results of the top oil temperature and hot spot temperature of transformer. The proposed simulation analysis method provides a new solution for hot spot temperature detection in pumped storage power plants.