Abstract: The change trends of the main pollutants of three centered drinking water sources of Chuxiong city were analyzed based on the water monitoring data from 2016—2020. It showed that the yearly averaged values of all monitored indices could reach the requirements of the corresponding water environmental function, and the water quality remained stable in general. However, the total nitrogen may be occasionally over the standard in the rainy season due to the increasing usage of drinking water and the shortage of the water storage of the reservoir and the decreasing of the capability of its self-purification. The countermeasures and suggestions were put forward on the basis of the present status of the surrounding environment of the reservoir and the environmental problems.