According to the Yalong River cascade reservoirs flood control capacity requirements in the Flood Prevention Schemes for the Yangtze River, this paper analyzed the impact of the reserved flood control capacity of the cascade reservoirs on the water storage and power generation. According to the characteristics of the Yalong River hydropower development, this paper put forward the solution of total quantity control of flood control capacity, established maximizing energy storage period model based on total quantity control of flood control capacity, analyzed the cascade reservoirs optimal storage schemes for 9 different inflow conditions, and offered the overall optimization strategy of cascade reservoir water storage.