Abstract:There are 1 267 species of seed plants belonging to 528 genera and 121 families, including gymnosperms (9 species, 6 genera and 4 families) and angiosperms (117 families, 522 genera and 1,258 species) in Laojun Mountain Natural Reserve in Pingshan County, Sichuan Province. Thirty-nine pantropic families account for 44.83% of the total families, while 114 north temperate genera amount to 23.55% of the total genera. The flora of Laojun Mountain Natural Reserve is close to the semitropical type which is spread in Hengduan mountains, Middle China and East China, though it is in the cross area of Yunnan, Guizhou and Guangxi characterized with the transition from tropical to semitropical zones.