In order to study the characteristic and regular of spatial and temporal variation of flux of Taihu Lake inflow pollutant in Tiaoxi Basin, one-dimensional hydrodynamic and water quality model is established based on synchronous monitoring of hydrology and water quality in Tiaoxi Basin. According to hydrological data from a dry year P=90%(2003), a normal year P=50%(1995), and a wet year P=20%(1981), and data of pollutants discharge in 2011, the flux of inflow pollutant in each typical year was calculated using the validated model of Tiaoxi Basin. Further analysis of the effect weight of cross-regional pollutant was done according to the calculation of the pollutant flux in rivers which run in or out of the district. Thus the foundation of tracing the source of pollutants was established. The results indicate that: (1) The flux of inflow pollutant component of COD、NH₃-N、TP、TN in wet years are 29 111、1 828、347、6 712 t/a, respectively; in normal years are 21 297、1 248、272、6 087 t/a, respectively; and in dry years are 14 243、898、187、4 078 t/a, respectively. The flux of inflow pollutant in wet years and normal years is larger, while in dry years it is smaller; (2) The weights of influence of inflow pollutant from each district in different typical years are ordered from large to small as follow: Wuxing District(partly); Deqing County(partly); Anji County; Linan City; Yuhang District(partly). Therefore, pollution control of Wuxing district is the key to inflow pollution control in Tiaoxi Basin.