Abstract: At present, aeolian sands are widely distributed in the source region of the Changjiang (Yangtze) River, where desertification has become a significant environmental issue. We systematically examined the surface characteristics of quartz, grain size distribution, geochemical properties, and detrital zircon U-Pb ages of aeolian sands in this region, to elucidate their provenance and formation mechanisms, and provide insights to inform ecological protection and desertification control efforts. (1) Results show that the aeolian sands are predominantly composed of poorly sorted fine sands in low roundness. The quartz grains exhibit mainly angular, sub-angular, and sub-rounded shapes, which is consistent with the characteristics of alluvial deposits. Additionally, the aeolian sands show a low degree of chemical weathering, with most grains having undergone only initial recycling. (2) Regarding provenance, detrital zircon age analysis revealed that the primary source areas are the Northern Qiangtang terrane and the Tanggula Mountains, containing a significant proportion of Cenozoic young zircons. This offers valuable insights into the magmatic history and tectonic evolution of the Tibetan Plateau, as well as the evolution of the Changjiang River. The findings suggest that the aeolian sands in the source region are derived from the alluvial deposits of the Tuotuo River. These sands are subsequently transported and accumulated by wind, forming as a product of physical weathering processes such as glacial erosion, cryogenic weathering, and abrasion or collision. Currently, desertification in the source area is mainly associated with the reactivation of these ancient aeolian sands, and future efforts to prevent and control desertification in the region should focus on the areas where ancient sand dunes are distributed.