In order to provide reference for the decision-making of the cascade development plan and engineering scale of the Tiger-Leaping-Gorge reach cascade, and promote the early start and effectiveness of the project, we established the joint operation model of controlled water projects in the upper reaches of the Yangtze River based on boundary conditions considering the regulation and storage of the controlled reservoirs, the existing and constructing transbasin water transfer projects and the additional water consumption outside the river channel. By using the model, we calculated and analyzed the utilization of the reservoir’s own storage capacity of different regulating storage schemes in the Tiger-Leaping-Gorge reach. The water resource utilization benefits of downstream cascade hydropower stations was analyzed using power generation indicators as a representative. Through analysis and demonstrates, it is believed that, to meet the requirement of reserving 5.86 billion m³ of flood control storage capacity during the flood season, the Tiger-Leaping-Gorge reach set with 6 to 12 billion m³ regulating storage can fully utilize the hydraulic resources of this reach and increase the average annual power generation of downstream cascade hydropower stations from 5.62 to 11.94 billion kW·h for many years, and from 16.15 to 29.40 billion kW·h for many years during normal water periods and dry season. Further increasing the regulating storage can have more significant compensation benefits for downstream cascade hydropower stations, but the utilization rate of storage capacity is relatively low, and the marginal effect decreases rapidly.