The genus Thibetana Efetov & Tarmann, 1995 includes six species occurring in southwest China and Indian Sikkim. In the present paper, Thibetana weii Li & He, sp. nov., the seventh species of the genus encountered at the foot of Galongla Snow Mountain, southeast Xizang of China is described. Habitus of the adult and genitalia of the new species are illustrated, and a checklist and a key of all Thibetana species are provided