Abstract: Based on the statistical analyses of the geographical elements of genera and species, and studies on distribution and relations between Hainan and its neighbouring regions, this paper concludes the flora features as follows:1.This flora of Bambusoideae is rich in Hainan species endemic.The amount (percentage) of Hainan species endemic is 27(71.05%), more than every area on the mainland of China.2.The geographical elements are obviously characterized by tropical nature.3.The distributions of species (or species endemic) on different parts of Hainan is clearly different.On the all parts of Hainan, the southern Hainan is richest in species (or species endemic), the species on the northern Hainan is poorest, the amount of species on the eastern Hainan is more than on the western Hainan.4.The origin of the Bambusoideae flora of Hainan is ancient and the flora is rich in primitive taxa.All the genera are divided into 8 primitive genera (with 8 stamens) and 6 advanced genera (with 6 stamens).5.There are more relations with neighbouring Guang Dong flora of Bambusoideae than with any other area on the mainland of China.

Key words: Floristic characteristics, Geographical distribution, Hainan, Bambusoideae