Taihu Basin water quality management decision support system (Taihu DSS) was developed for water quality management of river network in Taihu Basin.In the summer of 2000 algal blooms occured in Taihu Lake.Wangyu river was considered as the pilot river drawing water from the Yangtze River to Taihu Lake to solve the problem under emergancy time.So Taihu DSS was used to study the technique scenarios for drawing water from the Yangtze River to Taihu Lake through Wangyu river in different ways.To compare with the water quantity and water quality of Wangyu river entering Taihu Lake in different scenarios, the scenario that Wangyu river waster water was discharged through Li river gate into Grand Channel was adopted, which made Wangyu river drawing water from the Yangtze River to Taihu lake successfully in 2000, and deepened further research and the test.