Abstract: Daihai Lake Basin, a typical farming-pastoral ecotone, is an important part of the northern sand control belt in China's “two screens and three belts” ecological security strategic pattern, as well as an important part of the ecological barrier in the Beijing-Tianjin-Hebei Region, and its eco-environmental protection is of great significance. In view of the unique geographical characteristics and habitat conditions of Dahai Lake Basin, and centering on the two core issues of water quantity reduction and ecological degradation, the priority list of water quantity, water quality and water ecology was sorted out. With the guarantee of the ecological security of Dahai Lake Basin as the core goal, and in accordance with the idea of combining the optimization of ecological space management and control with the accurate restoration of zoning and classification, the land space management and control system of “one lake and three districts” and the ecological protection and restoration project system of mountain-river-forest-farmland-lake-grassland of “two increases, two decreases and three balances” were constructed. It was expected to strengthen the ecological service function of Daihai Lake Basin and promote the socio-economic development of ecologically fragile areas in the ecologically fragile farming-pastoral ecotone.