By using of ARC/INFO and varied information, pictures, data from (1) the map of Taihu lake basin's topography (1 :200000) by Nanjing Institute of Geography, Academia Sinica; (2) the map showing the velocities of the recent crustal vertical movement in the Yangtze River and its adjacent area by Hu Huiming, Huang Liren and Yang Guohua^[3] ; and (3) the forecasting of absolute sea level changes in the front of 21st century by Zhu Jiwen and Xie Zhiren^[4]', this report has build up the Geographical Information System about the sea level of the China' s Eastern sea coast region and ground changes of Taihu lake basin. The results forecast four different rise of sea levels (RSL) under aboslute sea level changes in the early 21st century, as well as the lowering of the high tide of Taihu lake basin correspondingly (i.e. 2000a, 2025a, 2050a). All of the forecasting results will not only be demonstrated by screen, but also be drawn and printed. The GIS supplies the fundamental data and analytical service about the sea level and ground changes of the Taihu lake basin.