Taihu Lake basin is the most important economic area in China with its catchment are being 36500km².Five sixths of its area belongs to plain, where many important cities such as Sanghai, Wuxi, Suzhou, and Houngzhou are locatcd. This water system includes Taihu Lake as its center combined with nearby river network. For the harness of the lake, stress is laid on the flood control, water supply, water resource protection and navigation.In order to make gcod use of Taihu Lake's regulation and to gain great comprehensive cfTicicncics in the Taihu Lake basin, tenitem key eng ncerings are laid out, among which are the Wangyu Canal and Taipu Canal. 80% of flood water from upstreams can Pow through these canals and 2.8km³ water from the Yangtzr River per year can be diverted so that the flood and water pollution maybe controlled.