Pollution is getting more serious in Taihu Basin with the rapid development of economy. In order to study the trend of water quality in Lake Taihu and the 22 major rivers into Lake Taihu, and their relationships. The total nitrogen, total phosphorus, ammonia nitrogen and permanganate index are analyzed using monitoring data from 2007 to 2014 by administrative divisions. Based on the analysis results, the rivers in Jiangsu Province are generally of higher pollutant concentration than the ones in Zhejiang Province since 2007. But the situation is improving in the 22 major rivers and the concentration changes of the rivers are closely related with the changes in Lake Taihu. It validates that pollutant transportation of rivers is the main pollutants of Lake Taihu and impacts on the changes in the water quality in Lake Taihu, and control of pollutants of the inflowing rivers is an important way to mitigation and treatment of pollution in Lake Taihu.