he Zoumatang channel dredging and expansion project is one of the important drainage projects that have been arranged by Comprehensive Management Plan of Water Environment in Taihu Basin ratified by State Council. The project aims at solving the drain path problem in the west side of Wangyu River during the Wangyu River helping Taihu Lake with diversion of Yangtze River period. The water logging of the west side of Wangyu River will be drained by the Zoumatang channel to the north into Yangtze River instead of drained into Wangyu River. The author analyzed the influence of Zoumatang drainage system on the water environment of Yangtze River.