Abstract: The ecological treatment measures and methods in the Taihu Lake were analyzed and summarized, and the numerical simulation method adopted to establish a two-dimensional plane hydrodynamic and water quality model. According the simulated results of different dominant wind direction combinations of southeast, northwest and northeast, the flow field variation regularities and streamline variation forms of the Taihu Lake were analyzed. Under the new idea of reducing invalid closed circulation system and improving the contaminant exchange rate through artificial diversion, the construction of diversion dike with the combination of sludge dredging, waterway dredging and landscaping engineering in the Taihu Lake was proposed, which could barrier the invalid endless loop system forced by wind, organize and guide the water flow, promote water cycle, and then improve the clean-up effective significantly. The results show that it plays an obvious role in promoting contaminant exchange rate of the Taihu Lake. Among the five diversion dike schemes, Scheme 5 is the optimal one with most obvious improvement of the contaminant exchange rate.