Abstract: Pumped storage technology plays an important role in maintaining the power balance of power systems and improving the operational stability of energy systems. Scientific capacity planning of pumped storage power station can help achieve economic operation of the power system, promote renewable energy development and save energy resources. In this paper, a comprehensive decision-making method based on Delphi method, interval-valued intuitionistic fuzzy theory, gray correlation theory and prospect theory is proposed for the capacity planning of pumped storage power station in hybrid wind-thermal-pumped storage power system. The proposed method considers the uncertainty of qualitative indexes, the inter-influence relationship among indexes and the risk preference of decision makers. Test results show that the proposed method can decide the optimal capacity planning scheme adapted to different risk environments, and can provide a reference for the capacity planning problem of pumped storage power stations.