Abstract:Ailaoshan Nature Reserve is located in the centre Yunnan Plataeu (23°36′～24°56′N，100°44′～101°30′E) with area about 677 km2 and altitude from 422 to 3 165.9 m, and involve three prefectures and six counties of Yunnan Province. On the basis of more than 4 000 seed plants specimens collected at the core area of Ailaoshan Nature Reserve and other regions nearby and 10 000 information obtained from the main herbaria of China, the floristic characteristics of seed plants of Ailaoshan Nature Reserve were studied. There were 2 453 native species (including subspecies) of seed plants belonging to 199 families and 945 genera in Ailaoshan region. The flora was Subtropical in nature basically with transition from Tropical Asia to Temperate East Asia. At family level, 105 families, accounted for 70.47% of the total families were Tropical distribution. At generic level, Tropical elements contributed to 63.89% of the total flora. The flora was lack of typical Tropical elements, but had many East Asiatic families and genera. The flora belongs to the Yunnan Plateau Region of Sino-Himalayan Subkingdom, East Asiatic Kingdom in floristic regionalization.