Abstract: In order to identify the phosphorus pollution characteristics of the inflow rivers, Poyang Lake, a hydrology and water quality survey was carried out during the year of 2017. The surveyed rivers covered the main branch of Gan River, the east branch of Fu River and the west branch of Xin River, which are three main inflow rivers of Poyang Lake. Temporal and spatial distribution characteristics of phosphorus concentration and composition were examined and the influence of hydrologic factors on the characteristics of phosphorus pollution was analyzed. Meanwhile, the sources of phosphorus were explored. The results showed that the average annual phosphorus flux of Gan River contributed most of phosphorus pollution in Poyang Lake, the form of phosphorus of the three rivers dominated by dissolved total phosphorus-based, the phosphorus pollution was significantly influenced by the hydrologic factors. The research indicated that the phosphorus concentration and morphology of the three rivers have difference. The change rule within the year was of great different as well.