Abstract: The penetration rate of new energy is increasing, and the output of new energy has a great impact on the safe and stable operation of power grid. The continuous storage capacity of cascade hydropower and the rapid regulation ability of hydropower units can smooth the photovoltaic output and improve the security performance of power grid. Based on the two typical application scenarios of wet season and dry season, this paper introduces the structure configuration and function design of cascade hydropower, photovoltaic and pumped storage coordinated optimization control system, and analyzes the control strategy by engineering examples. The simulation results show that the average fluctuation rates of the output of the cascade hydropower, photovoltaic and pumped storage combined operation are 1.7% and 1.9% respectively in wet season and dry season.All of them are lower than 3% of the dispatching requirements. The results of the study can provide reference for improving the power quality of other areas.