Lake Taihu has been seriously polluted recently, and the quality of the water environment has been declining year after year. The situation of the water environment in Lake Taihu directly are affecting the region's economic and social development, sothe protection of Lake Taihu has been listed as a national key treatment project. Based on the tour hydrometric gauging data and thewater quality monitoring results in the main stream channels entering the lake during 1998-2007,this paper analyzed the wateramount into the lake, and the water quality in the main stream channels discharged into the lake, and the amount of pollutants dis-charged into lake, as well as their variation trends, which will provide technical support and decision-making basis to the water en-vironment comprehensive treatment of Lake Taihu basin. Key words : The amount of pollutants analysis Lake Taihu Jiangsu Province