Combined with the cloud model theory, 10 quantitative indexes such as per capita water, per capita water supply, water resource utilization and development rate, etc. are selected to set up early-warning grading index system of sustainable water resources utilization in Xian City. The weight of each index is determined with the entropy weight method. The results show that compared with fuzzy matter-element method and fuzzy analytic hierarchy process method, the results of grading warning cloud model based on entropy weight are more reasonable and the utilization of water resources in Xian is in a relatively normal stage. Judging from the comprehensive cloud membership degree, the early warning of water resources sustainable utilization is ranked in proper order from high to low: Lintong District, Xian City, Changan District, The Hu Yi District, downtown area, Zhouzhi County, Gaoling District and Lantian County.