Abstract: Taking the Ningxia Yinchuan metropolitan area urban-rural east water supply project and its water supply range as the research ob‐ject,this paper establishes a multi-objective mathematical optimal allocation model of water resources,economy and environment and solves the multi-objective problem by the non-dominated sorting genetic algorithm-II（NSGA-II）.The hypervolume （HV） index is used to evaluate the convergence and distribution of the Pareto solution set obtained at different iterations.Considering the computing time,conver‐gence and distribution,the Pareto solution set obtained at 700 iterations is determined as the basis for subsequent data analysis and calcula‐tion.By calculating the fuzzy membership degree of each target value in the scheme set and analyzing the pairwise relationship between each target,it is found that there is a negative correlation between water resources objectives and economic objectives,as well as economic objec‐tives and environmental objectives,and a positive correlation between water resources objectives and environmental objectives.Then,the weight of each objective is determined as （0.48,0.32,0.2） by using the method of two elements contrasting.The multi-objective fuzzy opti‐mization model is used to screen the Pareto solution set,and the scheme with the largest superior genus degree （u_i=0.757） is determined as the optimal scheme.Under the optimal scheme,the groundwater consumption is 9 932.9 thousand m~3,the surface water consumption is64 569.0 thousand m~3,the economic target is 40.745 billion yuan,and the environmental target is 1 040.9 thousand kg.This scheme can realize the optimal allocation of water resources and provide a reference for regional decision makers in water resources allocation.