Due to the imp}scts of Gexhou Dam key water-control project and lower Jingjiang curve--cutting project after they were completed in the middle reach of the Yangtze River. Its current velocity in the affected section increased,river bed coarsened, coming branch channels were blocked, the river bed are un-dergoing a rapid ehange,and the eoanter-current eddies disappeared, thus spoiling and ruining ecological environment for the rare animal, Baiji. Its distribution area is thereby shortened toward the lower reach of the Dam. When the field expedi-tions in river section under research in 1986 to study the impacts upon the Baiji caused by these projects were conducted,its distribution had reduced from Yichang downward to Yidu only 50 kilometers away from the Dam,but it again. redu-cad from Yidu downward to Shashi, 160 kilometers away from the Dam The dis-tribution density of Baiji in the river section of auchiliau-Chenglingji(158 kilome-ters) was gradually rarefied. Its distribution density in, the section under research rarefied from 3.67km/per dolphin, in 1986 to 10.36km/per dolphin in 1991.Them Baiji has been listed as first-class animal under the protection of Chinese Government, but its population size remains smaller and human activities still se-verely endanger its existence. With human exploitation of tha Yangtze River fur-ther，new key water-control project will be built. Hence, a conservation strategy must be adopted to rescue this species.