Abstract:At present, the water quality of Honghu Lake is the most important ecological environment problem.Jiangling County, as the upstream of Honghu lake Basin, the surface water quality of Jiangling County directly affects the water quality of Honghu Lake.This paper analyzes and evaluates the change trend of total phosphorus concentration of surface water in Jiangling County by collecting data from rivers, lakes and channels in 2018-2023 year.The results show that the water quality of river and channels water in Jiangling County has occurred an increases at first and then decreases.The Ⅱ-Ⅲ of water quality grades was accounted for 62%,60%,76%,96% and 67% in 2019,2020,2021,September 2022 and May 2023,respectively.The concentration of total phosphorus in lake water showed a decreasing trend, which gradually improved from Class Ⅳ to Class Ⅴ in 2018 to class Ⅲ to class IV,and even increased to class Ⅱ in some lakes.Correlation analysis showed that there was significant positive correlation between phosphorus concentration and population density and number of enterprises, and agricultural non-point source pollution also significantly affected phosphorus concentration in water bodies.It is suggested to further strengthen the ecological treatment and regulation of industrial sewages, urban domestic sewage and agricultural non-point source pollution sources, and strengthen the ecological restoration of wildlife and plants in lake wetlands, so as to provide important technical support for water ecological environment management and protection in Honghu lake basin.