Based on the principle of fairness and efficiency,the paper set up water allocation index system and water allocation projection pursuit (PP) model. It used SCE-UA algorithm to optimize to optimize the best projection direction of PP model,and built SCE-UA-PP water allocation model.Taking the water allocation of water resources in Wenshan district for example, the paper compared it with the results of right allocation method.The results showed that SCE-UA algorithm has faster convergence speed, higher precision and better optimization convergence stability. The water allocation results of SCE-UA-PP model have more scientific and objective than that of the current method. The model and method can provide reference for water allocation.