This paper demonstrates the features of Dongting Lake, Hunan Province, and the importance and feasibility of its harnessing. If no measures are taken urgently, the lake may be extincted in about 100-500 years, as a result of huge accumulation of sediments from the Yangtze River and other rivers. It is suggested that Dongting Lake be tackled in a comprehensive way to reduce water source and develop drainage, i.e. to harness the Yangtze River first, and then to increase reservoir and drainage, i.e.to harness the lake itself, and to maintain and strengthen flood defense works.