Abstract: In view of the shortcomings in the traditional Nemerow index evaluation method,the analytic hierarchy process and the entropy weight method are used to combine subjective and objective weighting methods to improve the ignorance of the impact of the weight of each pollution index on water quality,and the method of calculating the revised maximum pollution index weakens the leading role of the largest pollution index. Finally,taking Bai River in Nanyang City as an example,the improved Nemerow Index method is used to evaluate the water quality pollution indicators of the four monitoring sections of Bai River from 2015 to 2018,the inverse distance weight method is used to analyze the spatial changes of water quality grades. The results show that the water quality of Dingfengdian Village,Wolong District,Nanyang City is Grade IV every year,and the water quality of the remaining sections are all Grade III or above. There are no Class I and Class V water quality areas in the spatial distribution of grades;in the temporal distribution of water quality grades,the area of Grade III water tends to increase,and the area where Grade IV water appears gradually decreases,and the overall water quality tends to get better. The results serve as a reference for the evaluation of water pollution and pollution discharge supervision in the basin.