Considering the multidimensional scheduling needs of flooding and sand transport, ecological environment and social economy in the Yellow River Basin, a multiobjective optimal scheduling model of watersediment, ecoenvironment, and socioeconomy is constructed for cascade reservoirs. The decisionmaking model is constructed based on modified cumulative prospect theory (MCPT) to optimize the scheduling scheme. Take Longyangxia, Liujiaxia, Haibowan, Wanjiazhai, Sanmenxia and Xiaolangdi cascade reservoirs as an example to construct and calculate scheduling decisionmaking models in wet, normal, and dry years. The results show that the sediment discharge and ecological objectives are somewhat competitive, the sediment discharge and power generation objectives are strongly competitive, while the ecological and power generation objectives are somewhat cooperative. The competivecooperative relationship among the three objectives is obvious in the dry year. Compared with the real scheduling scheme, the three target values for wet, normal, and dry years are all improved to different degrees. Compared with the commonly used decisionmaking methods, the sensitivity of the MCPTbased decisionmaking method is improved by several times, which is applicable to the situation where a large number of schemes need to be optimized for decisionmaking.