Dongting Lake, situated in the south of the middle reaches of the Changjiang River, is the second largest freshwater lake in China.According to the properties of sediments in Holocene and ancient cultural relics in various periods, as well as pollen data and historical records, the evolution of Dongting Lake can be divided into six stages. From later Pleistocene to early Holocene, Dongting Lake area was an alluvial plain with several small lakes and incised rivers since the level of the Changjiang River was 20-40 m lower than that of the present.During 8000-5000 a B.P., with the rise of the water level in the Changjiang River resulted from high sea level, as well as Wcirm palaeoclimate and plentiful rainfall, the water of four inlet rivers was jammed into this area to turn Dongting Lake into a large lake,an area starting from the Yuanjiang River mouth to Yueyang with a width trf 17-33 km.During 5000-3000 a B.P., the former large lake was divided by the fouMiver compound delta into several small lakes auid swamps due to dry palaeoclimate.During 3000-1700 a B.P., more than five large lakes and many swamps were formed in the lowland.From 1700 a B.P.to the 19th century, with the formation of Taiping Breach and Ouchi Breach relevant to the burst bank of the Changjiang River, and plentiful precipitation, Dongting Lake reached its largest area of 6000 km².Beginning from the middle of the 19th century, as 0.984×10⁸m³/a of silts carried in by the Changjiang River and four inlet rivers and a large-scaled reclaimed land from lake, Dongting Lake decreased rapidly to 2691 km² in the 1980s.