Xiaoxinganling-Sanjiang Plain is the original ecological security barrier of northeast (north) China. It is a key area of biodiversity and also a key food production base in China. Its eco-environmental protection has attracted much attention. According to the regional characteristics of the Xiaoxinganling-Sanjiang Plain, major eco-environmental problems in the region were identified from forest, mine, grassland, wetland, water and other elements. On the basis of defining the regional functions, the design idea, general layout and specific engineering scheme of ecological protection and restoration programme of mountain-river-forest-farmland-lake-grassland were put forward. It revealed that the main eco-environmental problems in Xiaoxinganling-Sanjiang Plain included the weakening of forest water conservation function, the ecological destruction of abandoned mines, the reduction and degradation of grassland area, the shrinking of wetland area, and the decline of partial water function. According to the optimization of the ecological space control combined with zoning classification precision repair, combined with the area of lakes, mountains, rivers, and other important natural geographical boundaries, it was proposed to build the overall layout of “two barrier, one belt, and one zone” (Xiaoxinganling ecological security barrier, Wandashan ecological security barrier, Songhua river water and soil pollution prevention and control belt, Sanjiang Plain wetland biodiversity conservation zone). On this basis, five major projects, including forest protection and restoration projects, mine environmental control projects, land regulation and restoration projects, biodiversity protection projects and water environmental protection and control projects, were promoted as a whole. The implementation of the programme was expected to bring good ecological, social and economic benefits to the region.