Abstract: In the current context of large-scale integration of wind power and photovoltaic power into the power grid, the key task to ensure the stability and efficiency of energy supply is to determine the appropriate penetration rate of renewable energy and accurately match the capacity of renewable energy and energy storage systems. Therefore, considering the uncertainty of wind and solar energy, this paper constructs a wind-solar-pumped storage-thermal optimal scheduling model of the combined operation system. Firstly, the Latin hypercube sampling method is used to simulate the output scenarios of wind and photovoltaic power within the model. Then, the generated output scenarios of wind and photovoltaic power are reduced through a simultaneous backward reduction algorithm based on Kantorovich distance, and the model is solved by an improved particle swarm algorithm. Finally, taking the Bailianhe Pumped Storage Power Station as an example, combined with local measured wind speed and solar radiation data, the dispatching results with or without pumped storage participation and different energy capacity ratios are explored. The following conclusions are obtained:（1） The addition of pumped storage power stations has increased the revenue of the hybrid generation system by 4.280 6 million yuan, reduced the volatility of wind and photovoltaic power output by 12.24%, decreased the abandonment rate of renewable energy by 5.62%, and reduced pollutant emissions.（2） The ratio of pumped storage to renewable energy installed capacity is reasonable in the range of 1∶8.33, and the renewable energy abandonment rate is the lowest at 1∶5.21.（3） When the ratio of pumped storage to renewable energy installed capacity is 1∶6.25 and the penetration rate of renewable energy is 71.09%, the hybrid generation of wind-solar-pumped storage-thermal system has the greatest marginal benefit.