Abstract: Traditional reservoir operation is mainly designed for water supply and/or flood control,and the purpose of the ecological reservoir reoperation is to achieve the ecological and environmental objectives:water quality,ecosystem,sediment and disease control etc. We propose an ecological reservoir reoperation model based-on ecological flow regime. The model takes the maximum of reservoir benefit,such as annual power generation as the objective subject of the ecological scenarios. The ecological reservoir reoperation model is applied in a tributary in the Yellow River basin as an example.Based on the status quo of the watershed,four ecological and environmental objectives are given and five ecological scenarios are proposed. The results of the model indicate that the annual power generation only decreases by 7.6% with all the four objectives met than the non-ecological objective. According to the results,the hydropower benefit of the reservoir will not decrease dramatically while the ecological demand can be met,if we introduce a suitable reoperation pattern.