Abstract: Based on the Landsat TM and ETM data acquired at the end of 1980's and 1990's respectively, the authors analyzed the characteristics of land use/cover changes in the Dongting Lake area through GIS analytical method. Runoff in 1989 and 1999 was calculated using rainfall pattern in July of 1996. The results show that the characteristics of land use change in Dongting lake area are reflected in the decrease of the cultivated land and the increase of construction land and the water area . The main conversion of land use include four types: paddy field converted to builtup areas and water, the area of forest transformed to builtup areas and dry land area converted to construction land. Compared to 1989,runoff increased by 206×105 m3 in 1999 if 1996 precipitation was used. The increase of the construction land is the main reason that runoff increases in this period. Land use change influenced the runoff and confluence process in flood season. To strengthen the land management in flood area and the rational control and adjustment of land use status will lighten the threat of flood disaster.

Key words: DongtingLake Area, land use change, runoff