According to the impact on economic development，impact on social development，impact on the environment，build the irrigation continuous construction and water-saving reform engineering social impact assessment index system.The fuzzy hierarchy comprehensive evaluation model based on entropy combination weight is used to combine the subjective and objective weights to form the combined weights with the relative minimum entropy as the tool.On Yinwan bridge Irrigation District continued construction and water-saving reconstruction project supporting the social impact of comprehensive evaluation，determine the social impact evaluation grade is grade II.Results show that the evaluation result can better reflect Yinwan bridge irrigation area corollary and water-saving reconstruction project characteristics and are in agreement with the local engineering actual situation.It shows that the comprehensive evaluation method is reasonable，scientific and feasible.