Cage culture is the main source of pollution to the water environment of reservoirs, to which the influences it may introduce, is important to be assessed. Based on the case study of one large reservoir in Jiangxi province, this article brought up analysis and discussions about the causes of pollution sources, as well as the effects of the cage culture has on the water quality of the studied reservoir. Several strategies were proposed in this article in order to offer advices and references to improve the conditions of the water quality of this reservoir.