Abstract: Danjiangkou Reservoir Region,located in the juncture of Hubei Province and Henan Province,is the water source of the middle-route of South-to-North Water Transfers Project in(China).Abundant aquatic vascular plant species,including 90 species belonging to 56 genera and 30 families, were found in the area.Among the 9 areal-types of its genera distinguished,cosmopolitan,pantropic and north temperate distribution patterns were the main floristic elements,which implied the subtropic characteristics of the wetland.The comparison of flora between(Danjiangkou) Reservoir Region and other 9 wetlands showed that the geographic position and climate history affect the flora similarities.