Taihu Lake is a large shallow lake, located in the Delta of the Yang tze River.The hydrodynamic processes exert a profound influence on the lake environmental evolution.Based on the f ield investigation in Meiliang Bay, Taihu, in the summer of 1998, this paper at tempts to summarize the water current pat tern during the summer prevailing wind forcing.With the prevailing of southeast wind, the water current shows a clockwise circle, i.e.the water flows northward in the western coast and southward along the eastern coast.But in the northeast, close to the mouth of Liangxi River, a small inconsistent water current pat tern is presented.In the presence of above water current pat tern, the dist ribution of Chl-a concent ration, as well as the total nit rogen (TN) and to tal phospho rus (TP), shows a pattern associated with directions of water flowin the Meiliang Bay, i.e.Chl-a, TN and TP most ly concentrated in the northeastof Meiliang Bay.But the total dissolved nitrogen (TDN)and total dissolved phospho rus (TDP)concentrated in the northwestof bay because these components are less af fected by the transportation of water flow.The solid suspension (SS)concentration changed with the intensity of wind forcing and with water depth.The investig ation found that the concent ration of SS at the mouth of bay is g reater than that in the bay.Moreover, SS increased dramatically when the wind speed greater than 5m·s^-1, but slig ht difference with the water depth if wind speed less than 4-5m·s^-1, which indicated a high concent ration of organic mat ter in the upper layer of water.These findings will be very helpful for the protection of drinking water source, and understanding the relation between hydrodynamic processes and water transparency, primary productionn, etc.It is also of importance for the const ruction of Taihu Lake environmental management model.