[Objective] The land-use changes from 2000 to 2020 and in the future (2100) under different development scenarios in the arid region of Northwest China were studied, and the changes in carbon storage and carbon source/sink caused by land-use changes were analyzed, in order to provide a reference for regional land management optimization, carbon sink increase, and environmental protection.[Methods] Based on land use data from 2000 to 2020, the FLUS model was used to simulate the land use situation in 2100. The carbon storage, carbon source/sink, and carbon changes in regional ecosystems in 2000-2020 and in 2100 under different development scenarios were estimated and analyzed by using the carbon submodule of the InVEST model with the revised carbon density and land use data.[Results] ① From 2000 to 2020, the area of cultivated land, grassland, and construction land increased continuously, while the areas of forest land, water, and unused land decreased. The total carbon storage of the region increased by 1.60×10⁸ t during the 21 years, including 2.89×10⁵ t for vegetation and 1.60×10⁸ t for soil. ② Compared with 2020, carbon storage will increase by 6.37×10⁸, 7.78×10⁸ t, and 8.49×10⁸ t, respectively, under the natural development scenario, the cultivated land protection scenario, and the ecological protection scenario in 2100. The carbon storage capacity of the cultivated land protection scenario and the ecological protection scenario will improve significantly, and these will be important ways to increase regional carbon sink. ③ There was obvious heterogeneity in the spatial distribution of carbon storage values in Northwest China. The high-value areas of carbon storage (9 800~14 568 t) were mainly located in mountainous forest areas, while the vast desert and Gobi areas had low carbon storage values (1 600~5 800 t), and the distribution of carbon was closely related to the distribution of regional land use types. ④ From 2000 to 2100, the carbon source/sink area was nested and interlaced. The carbon source area was mainly located over the northern slope of the Tianshan Mountains, the oasis edge of the Tarim Basin, and the Western Kunlun Mountains. The distribution of the carbon sink area was basically consistent with the middle and high value areas of carbon reserves, and concentrated on the mountainous area containing extensive forest land and grassland.[Conclusion] The carbon storage in the arid area of Northwest China showed a continuous upward trend from 2000 to 2020, and the carbon storage in the future under the three scenarios also increased significantly, especially under the ecological protection scenario, which is conducive to the sustainable and benign development of the ecological environment