A high-precision 3D numerical model of wind-driven current in Taihu Lake and a coupled numerical model of wind-driven current and pollutant were built. The characteristics of wind-driven current in Taihu Lake were analyzed under prevailing wind condition. Moreover, the characteristics of pollutant transport and diffusion driven by wind-driven current were studied. According to the results, when the wind driven current in Taihu Lake is stable, the surface velocity is significantly higher than the bottom velocity and the surface flow is almost the same as the wind direction while the bottom flow is roughly opposite to the wind direction, which shows the characteristic of compensation current. Wind direction can significantly affect the morphology and structure of the wind-driven current in Taihu Lake. The mass concentration of pollutant in Taihu Lake is approximately evenly distributed along the depth of water under vertical diffusion effect. Under constant wind, several small-scale closed circulations can be found in the bay area of northern Taihu Lake, which is not conducive to the transport and diffusion of pollutants and also has negative effects on the water environment of Taihu Lake.