In order to study the pollutant flux influence of Sunan Canal on main inflow rivers of Taihu Lake, a 1-D water quantity and water quality model of the plain river network is established; the pollutant flux, including chemical oxygen demand(COD), ammonium(NH⁺₄), total nitrogen(TN), total phosphorus(TP), in main inflow rivers contributed by Sunan Canal is simulated; and the pollutant flux contribution rate of Sunan Canal on main inflow rivers is quantified. The results indicate that Sunan Canal mainly influence the inflow rivers in the west of Taihu Lake, which is quantified as 23%. Sunan Canal contribute most to Taige Canal(42%)and then Caoqiao River(21%). The pollutant flux contribution rate of Sunan Canal on South Taige Canal, Shedu River, Chendong River decrease successively from north to south.