Abstract: A background survey and a species observation on avian were conducted respectively in the Three Gorges Reservoir during 1996-1997,and 1999-2000.354 species,be longing to 17 orders and 51 families were recorded.Among them,153 (43.22%),164 (46.33%),and 37 (10.45%) species are the avian of Palaearctic region,Orie ntal region and Cosmopolitan respectively.There are 87 species (24.58%) of summer residents,63 species (17.78%) of winter residents,46 species (12.99%) of travelers and 158 species (44.63%) of residents.The birds of Passeriformes have more important contribution to the group diversity in the Three Gorges Reserv oir.Zigui County has the maximal family diversity,while Badong County has the upmost species composition.The research indicated that habitat diversity was the main key factors to control bird species diversity in a certain time and space.