By the synchronous environmental monitoring of 49 inflow and outflow rivers of Lake Taihu, this study analyzed the wa-ter quantity and pollutant fluxes of those rivers in 2009, and compared them with the literature data of previous years.Analyses showed that water fluxes of the inflow and outflow rivers were 88.40×10⁸m³ and 93.27×10⁸m³ successively in the year 2009, re-spectively.The 5 largest inflow water fluxes were in the order as Chendonggang >Dapugang >Liangxi River >Taige River >Wan-gyu River and the 2 largest outflow water fluxes were Taipu River and Changdougang.Analyses also showed that the river pollution from Yixing area were heaviest, and should be urgently improved.Also the outflow suspend particle fluxes were extremely larger than that of inflow and most of suspend particle was outflow in the south part of the lake.Furthermore, the total nitrogen and total phos-phorus fluxes increased since 2002.The project of water diversion from Yangtze River to Taihu basin was good for water quality of the lake.Comparison of water quality between the lake and rivers suggested that the inflow river pollutant had important effect on the lake water.