This paper studied the water volume of the Dongting Lake by using Terra/MODIS satellite data, water level and lake bottom DEM (Digital Elevation Model). As water has a high absorption rate in the near infrared and infrared band, the water area of the Dongting Lake was extracted by setting thresholds on NDVI (Normalized Difference Vegetation Index) and NIR (Near InfraRed). A water level distribution map was obtained by interpolating the water level data from hydrological stations. The volume of the Dongting Lake was estimated by using the water area map, the water level distribution map and the lake bottom DEM. The hydrological response of the Dongting Lake on the Three Gorges was studied by using the water level, area, and volume data. The result has shown that the method mentioned above can be used for water volume estimation of the Dongting Lake. The water area, water volume and water level have a high correlation. The water level of Chenglingji and water volume of the Dongting Lake was fitted by cubic curve, and the coefficients of the determination of the fitting curves were 0.915 and 0.928, respectively. The Three Gorges Project has shown the ability of flood storage after interception, and the cumulative water volume ratio of flood season decreased year by year from 2004 to 2006. At the same time, during late summer and early autumn, the impoundment of the Three Gorges Project causes the decrease of water discharged, which increases the drought of the Dongting Lake.