Nanling mining area in northern Guangdong Province is located in the core area of the southern hilly and mountainous region of the "two screens and three belts" of the national ecological security pattern. Due to historical disorderly mining, beneficiation, and smelting activities of non-ferrous metal minerals, the problems of the regional ecological environment are clear, as well as soil, water, and crop pollution in downstream areas. Restoring historical mines and controlling the sources are essential for solving the problems of regional ecological environments. Taking typical mine abandoned land units (waste dumps) as examples, in this paper, the engineering technology model and key technologies of ecological restoration were proposed, and pre-evaluation methods and practical research on repair benefits were performed. The results revealed that ecological environment problems in the Nanling mining area of northern Guangdong include:outstanding vegetation destruction and soil erosion in mines, a high risk of geological hazards, and serious soil and water pollution around mines. Mine ecological restoration should be based on the prevention and control of potential safety hazards, with restoration of ecological functions as the main objective, and control of soil and water pollution in mines. This paper constructed a three-dimensional ecological restoration model of Nanling waste dump in northern Guangdong, which follows the co-governance of the mountains-rivers-forests-farmlands-lakes-grasslands system, and remolds terrain according to the situation, guides water flow according to the situation, and stabilizes slopes with flexible protection. The key technologies of ecological restoration, such as site leveling, clearing and diverting, soil improvement, ecological bag planting of slope, and three-dimensional vegetation allocation, are proposed. It also establishes an ecological benefit evaluation model including water conservation, soil and water conservation, environmental purification, and water quality purification. It is estimated that the ecological benefit of waste dumps after restoration can reach 66754.25 yuan/a. These research results provide technical support for the co-management of the mountains-rivers-forests-farmlands-lakes-grasslands system in the Nanling area of northern Guangdong and similar areas.