Aiming at the contradiction of Yangtze river basin that the climate and hydrological changes , the decrease of water inflow , the impact of ecological environment and a large number of hydraulic facilities build in the upstream cann't meet the built water demand program, the paper built multi-objective optimization mathematical mode based on the original impounding and dispatching scheme of three gorges project in comprehensive consideration of flood control , power generation , navigation , the downstream drought water supply and the amount of the ecological water and other constraints,and put forward six impounding schemes ahead of flood end.According to these aspects of annual average fill storage rate,final water level,power generation,spill water and flood risk,comparing each impounding scheme ahead of flood end to determine the optimum one and was validated by taking the typical year of runoff being dryer to test.Results showed that the best optimal impounding scheme is the combination of conventional and ecological dispatching.The scheme can not only effectively control the risk of flood control of three gorges reservoir but also maximize the benefits and is the optimum one.