This project takes the stable restoration of sandy land as the primary goal. Based on the comprehensive study of the biological and physical processes of desertification, the project establishes an ecological kinetic model for the sandy land system in semi-arid deserts with the coupling of hydrology-soil-vegetation-wind erosion, analyzes the ecological mechanism of sandy land development and restoration, and constructs a database on the dynamics of sandy land in semi-arid deserts in northern China. We will analyze the ecological mechanism of development and restoration of sandy land, construct a database on the dynamics of sandy land in semi-arid desert areas in northern China, and elucidate the trend of evolution of sandy land. We will assess the carrying capacity of soil, moisture and vegetation in semi-arid desert ecosystems to maintain stability, explore the biological process and regulatory mechanism of stable restoration, identify the ecological thresholds for stable restoration of different sandy lands, form a technical system for assessing the health of semi-arid desert ecosystems based on the carrying thresholds, and put forward key biotechnologies to realize the stable restoration of sandy land. Construct an industrialized model of sandy land management in semi-arid desert areas with the main line of "scientific and technological support - ecological restoration - industrial development - social progress", and establish industrialized application demonstration bases for sand control and prevention adapted to regional characteristics in the Maowusu Sand, the eastern part of the Qubuzi Desert, the central and western part of the Horqin Sand and the Hulunbeier Sand. It will set up demonstration bases for industrialization and application of sand control and prevention to meet regional characteristics, and realize significant comprehensive ecological, economic and social benefits.