With the minimum overall hydrological change degree as the ecological goal and the minimum generalized water shortage index as the economic and social water supply goal, an optimization model of reservoir operation rules considering natural hydrological regime was established. Taking the Dalong Reservoir in Sanya City as an example, the optimization scheme of Dalong Reservoir operation rules is obtained based on the NSGA-Ⅱ optimization algorithm. According to the change of economic and social water supply and eco-hydrological index, different operation rules are analyzed, and the optimal operation rules considering economic and social water supply and river ecology are determined as the recommended scheme of Dalong Reservoir operation rules