Abstract: Water quality assessment of the Fenghe River Basin lays the foundation for the development and management of water resources in Xi’an. Exploring the temporal and spatial variation characteristics of Fenghe River water quality can provide technical support for the utilization, development and management of water resources in Xi’an. Methods of single-factor evaluation, grey relational analysis, Nemerow index and fuzzy comprehensive evaluation were used to evaluate the water quality of the Fenghe River Basin. The results show that the typical pollutants in the basin are TN, TP and NH₃—N. The overall pollution status of the river is as follows: midstream＞downstream＞upstream. It is found that Fengyu has the best water quality among the monitoring sections, whereas Yurufeng has the worst comprehensive water quality. The improved fuzzy comprehensive evaluation method proposed in the study can analyze the water quality from multiple aspects, which makes the evaluation results more objective and hierarchical. According to the evaluation results, the water pollution in Fenghe River Basin is mainly concentrated in the middle reaches of the basin. The research results are of great significance to the implementation of key projects in Xi’an, such as source control of sewage interception, water diversion from rivers and lakes, and water supply for the National Games.