Abstract: Polygonum hydropiper distributes widely on wetlands and the natural water-level-fluctuation zone along the Yangtze River.Its endurance and morphological changes were tested in this paper in order to know its adaptive mechanism and endurance to flooding from April to May.Results showed that the surviving rate of all treatments kept 100 percent,and that the length,width and area of leaf all reduced remarkably during the primary flooding time,and recover late along with the development of adventitious root induced by flooding.The adventitious root biomass increased significantly with the prolongation of flooding time,however,the plant height,branch number,branch length and burl space did not differ significantly among treatments,so were the plant total biomass,root biomass,above-ground biomass.All of these suggest that P.hydropiper adapts flooding by change in leaf shape and the development of adventitious roots.The results indicate that P.hydropiper is a potential species for the restoration of water-level-fluctuation zone in the Three Gorges Reservoir Area.