Abstract: Located in the northeast of the Qinzang Plateau, Qaidam Basin is a huge plateau-type closed basin. The vegetation is dominated by desert, including swamp wetlands, halophytic meadows and montane grasslands. In order to show the species composition, community characteristics and distribution pattern of vegetation in Qaidam Basin in more detail, this paper uses the field data of the Second Tibetan Plateau Scientific Expedition and Reserch of 2022 and the Comprehensive Scientific Investigation of the Data-scarce Area of the Qinghai-Tibet Plateau of 2014, including 157 sample plots and 458 sample plots, which are integrated into the sample data set of plant communities in Qaidam Basin. Through the collation and compilation of data, a total of 185 species information was obtained, among which the families with the largest number of species were Asteraceae (39 species), Poaceae (33 species), Fabaceae (17 species), Amaranthaceae (16 species) and Brassicaceae (10 species) , and the genera with the largest number of species were Stipa, Artemisia, Astragalus, Oxytropis and Saussurea. The composition of plant life form is dominated by herbs, accounting for 78.37%. The species of middle Asia account for 41.62% of the geographical composition of the flora. Based on the phytocoenological-ecological principles, 163 sample plots can be classified into 4 vegetation formation groups, 7 vegetation formations, 11 vegetation subformations and 40 alliances. This data set can provide the most original basic data for the in-depth study of vegetation characteristics in Qaidam basin, the compilation and research of the Vegegraphy of China, and the mapping of Qingzang Plateau and the national vegetation map.

Key words: Qaidam Basin, Quadrat data, Species composition, Plant community, Vegetation classification