Altun Shan National Nature Reserve () (literally, O You Golden Mountain) is a large, arid area in the southeast of Xinjiang Autonomous Region, on the northern edge of the Tibetan plateau and the southern edge of the Tarim Basin in northwest China. It surrounds the Kumkol Basin, an endorheic basin (no outlets to the sea) in the western third of the Altyn-Tagh mountains (Altun Shan). The reserve is sometimes referred to as the Arjin Mountains Nature Reserve, or Aerjinshan. The reserve covers the southern portions of Qiemo County and Ruoqiang County (including Qimantag Township (祁曼塔格乡)) of Bayingolin Mongol Autonomous Prefecture in Xinjiang.