Abstract: In order to protect aquatic system health of Wujiang River and achieve the win-win goal of the water energy resources development and ecological environment, the ecological operation of cascade hydropower stations along Wujiang River in Guizhou provience is studied. The minimum, suitable and ideal ecologically flow demands of the Hongjiadu, Wujiangdu and Silin stations were analyzed. And the multi-objective combination optimization scheduling model of Cascade Hydropower Stations there was built and solved. Mean annual and typical year generating capacity of 9 reservoirs are calculated. Ecological water period guaranteed rate and the scheduling process of 3 main control sections are showed. The results show that this study can increase the ecological water period guaranteed rate of Wujiang River, as well as guarantee benefits of flood control and power generation. As for low flow year, it is hard to reach the ideal ecological flow demand.