Abstract: Pumped storage power, as a flexible power for peak shaving and valley cutting, can compensate each other with nuclear power. Based on the combined operation mode of "nuclear power plant-pumped storage power plant", this paper analyzed the reasonable ratio of two power plants from output equivalence and economic benefit. Then, the impact of combined operation on the power system was analyzed and the reasonable scale of combined operation was obtained by 8760-hour production simulation and system power-generation cost analysis. Finally, based on the case study in a southeast coastal province, it shows that the combined operation of two power plants is feasible for not only guaranteeing the economic benefits of the power supply owners, but also reducing the system power-generation cost.