Abstract: In order to strengthen the watershed ecological environment control and further realize the refined management of water environment, a new way of delimiting the control unit is discussed. Through establishing a SWAT model, according to the characteristics of natural catchment, the distribution of non-point source pollution and the ecological red line division, we divide the water environment control unit and establish a water environment zoning management and control system for the Xiangjiang River Basin in Yongzhou City, Hunan Province. The results show that the whole basin is divided into 4 primary control units, 36 secondary control units and 115 tertiary control units, and the tertiary control units 3,39 and 96 are the key sources of non-point source nitrogen and phosphorus pollution. The classification control strategy of the primary control unit is proposed: basic control unit should focus on source mitigation and implementation of water conservancy and hydropower management; priority control units should promote the agricultural non-point source pollution control and soil erosion conservation; key control units focus on urban and rural environmental improvement and non-point source pollution control; general control unit needs strict environmental admission to achieve high-quality development and coordinate the protection of aquatic germplasm resources.