The primary objective of this project is to stabilize and restore sandy land. On the basis of comprehensive research on biological and physical processes of Desertification, an ecological dynamic model of sandy land system in semi-arid areas with "hydrology soil vegetation wind erosion coupling" is established to analyze the ecological mechanism of development and restoration of sandy land, build a dynamic database of sandy land in semi-arid desert areas in northern China, and clarify the evolution trend of sandy land; Evaluate the stable soil moisture and vegetation carrying capacity of the semi-arid desert ecosystem, explore the biological process and regulation mechanism of stable restoration, identify the Ecological threshold for stable restoration of different desertified lands, form a technical system for health assessment of the semi-arid desert ecosystem based on the carrying threshold, and propose the key biotechnology to achieve stable restoration of desertified lands; Build the industrialization model of desertification land control in semi-arid desert areas with the main line of "scientific and technological support - ecological restoration - industrial development - social progress", and establish industrialization application demonstration bases for desertification prevention and control that adapt to regional characteristics in Maowusu Sandy Land, the eastern Kubuqi Desert, the central and western Horqin Sandy Land and Hulunbeier Sandy Land, to achieve significant ecological, economic and social comprehensive benefits.