Abstract: This is an article in the field of mining engineering. The Southern Xizang is one of the main distribution areas of high temperature geothermal zones in China with rich geothermal resources. The chemical analysis and test results of the geothermal water show that the lithium content in the geothermal water of the high temperature geothermal zone in Southern Xizang can reach 34.51 mg/L, and the relative abundance of geothermal lithium is obviously better than that of the world's typical plateau Salt Lake brines, such as Clayton Valley in the Western Plateau of North America and Uyuni in the Andes Plateau of South America. The lithium magnesium ratio is mostly less than 3, which is conducive to lithium extraction from brine. The areas with high lithium content in the geothermal water of the high temperature geothermal zones in Southern Xizang are all distributed in the the Yarlung Zangbo River suture zone and the areas to the south, consistent with the distribution range of lithium rich rocks. At the same time, the Yarlung Zangbo River suture zone and its south area have more Cl-Na geothermal water than the north, and the south has higher TDS and longer circulation path. Based on the stable isotopic composition of hydrogen and oxygen in geothermal water and the provenance of lithium in the surrounding lithium-rich Salt Lake brine, it is inferred that the main sources of lithium in the geothermal water are leaching of lithium-rich rocks by geothermal water and lithium-rich magmatic hydrothermal solutions formed during magmatic differentiation.