Whereas the fact that Honghu wetland is representative in Jianghan (Yangtze-Hanjiang Rivers) plain as a Waterlogging accident-prone area, Honghu wetland was studied using the methods of Geographical Information System and Remote Sensing to find out its ability of storing floodwater and withstanding waterlogging. In this paper, TIN model was established, thereby the relationships between water level and water area of Honghu Lake and Honghu wetland were calculated, their relationships between water level and water volume were also computed. Through the overlaying analysis to the TIN model and the image of Landsat-ETM+ of July 2001, the average elevation of each wetland type was counted. Then the altitude of 23. lm was turned out to be the cultivation line of paddy field. From this, the sluice volume was calculated to be 1.087×10⁹ m³ on condition that the paddy is uninjured. At last, the advice of setting up a decision-making system of decreasing disasters based on GIS was put forward in order to be helpful to the work of decreasing flood and waterlogging disasters.