Abstract:Yunnan is a province rich in flora. There are about 13,000 species of 1,984genera alnong 240 families (230 families of Angiospermae according to Hutchin-sonts system and 10 families of Gymnospermae) in Yunnan. The number of family in Yunnan is about 79.73% of 301 families in China, the number of genera 64.8896 of 3,058 genera in China, and the number of species 52% of 25,000 species in China. The four very big families such as Orchidaceae, Compositae,Papilionaceae and Gramineae which contains 10,000 or more species in world-wide separately, all have a lot of species in Yunnan.