Abstract:The flora of Hong Kong was surveyed by the first auther during March 1996 toJune 1998 according to the Project of investigation on the Biodiversity of Hong Kong.More than 3 500 specimens were collected, of which some 100 species were new records toHong Kong. In this paper the history of floristic researches, the vegetation, the floristiccomponents, endemism, the rare and endangered species as well as a comparison of theHong Kong flora to the neibouring regions are presented. Hong Kong is rich in plant diversity， so far a total of 2 145 vascular species in 973 genera of 224 families，including 216 species in 97 genera of 45 families of ferns have been recorded, of which 16 species are listed to be protected by China government and 166 species by government of the Hong Kong. Special Administrative Region．The most species-rich families are Gramineae，Orchidaceae，Papilionaceae, Cyperaceae，Compositae Rubiaceae， Euphorbiaceae， Lauraceae， Fagaceae, Moraceae，Theaceae and Myrsinaceae the latter seven being dominants in forests The species-rich tree genera with more than 10 species are Ficus, Lithocarpus，Ilex，Machifus，Sympfocos，Castanopsis，Cyctobatanopsis and Camellia，all of which are also dominants and are of tropical and subtropical elements．As a part of Guangdong flora，the flora of Hong Kong is closely related to that of Hainan and Indo-China，and they share the same origin.