As China's largest freshwater lake and the international important wetland, the Poyang Lake has extremely valuable ecological function and plays an important part in maintaining the safety of regional and national ecological security. Due to the main transportation way of the particle Nitrogen (N) and Phosphorus (P), sediment and nutrients caused by soil erosion of the Poyang Lake watershed not only directly affect ecological functions of the Poyang Lake but also pose risk potential on mid-and down stream of the Yangtze River. Therefore the purpose of this study was to make an assessment of soil erosion and output load of the particle N and P in five sub-watersheds of the Poyang Lake, including Ganjiang river, Fuhe river, Raohe river, Xinjiang river, Raohe river and Xiuhe river in order to provide theoretical information for agricultural non-point source pollution management, ecological construction, and environmental protection in Poyang lake watershed. Based on data of the First National Agriculture Pollution Source Census and Soil Quality Survey of Jiangxi province in the Watershed in 2007, RUSLE model and spatial statistic function of GIS were used for assessing soil erosion and output nutrients (particle N and P) load in the Poyang Lake watershed. Results showed that the sediment transport modulus of the five sub-watersheds based on RUSLE in 2007 is reliable. The soil erosion load of Poyang Lake watershed amounted to 9913921t/a, in which Ganjiang, Fuhe, Xinjiang,Raohe, and Xiuhe Rivers accounted for 63.3%、9.9%、9.9%、6.2% and 10.7% of the total load, respectively, and the sediment transport modulus of each watershed above mentioned was 9.09、8.92、9.76、7.59 and 10.61 t · km^-2 · a^-1,respectively. Compared with that published in Changjiang Sediment Bulletin (CSB), as for sediment transport modulus errors of the five sub-watersheds, the maximum relative error is that from Ganjiang river sub-watershed as high as 66.7%,the minimum relative error is that from Raohe river sub-watershed as low as 11%,and the average error of these five sub-watersheds was as much as 42.3%. Furthermore, output loads of erosion sand, particle N and particle P transportation were 12451831, 33831 and 731 t/a in the Poyang Lake watershed, respectively. Among these output loads, the adsored N and P from the Ganjiang river sub-watershed was the biggest, more than any of other sub-watersheds, accounting for 58.1% of the total load of the Poyang Lake watershed. The output nutrients load from the Fuhe river, Raohe river, Xinjiang river, and Xiuhe river accounted for 11.2%, 7.2%, 11.3% and 12.2% of the total load of the Poyang Lake watershed, respectively. Compared with output loads of TN and TP from agricultural pollution sources, the erosion sand load from the Poyang Lake watershed was relative high, but the output loads of the adsored N and P from the watershed were low, which were proved not the primary source of nutrients in the Poyang Lake. Due to difficulty of getting spatial distribution data of the nutrient background contents in the whole Poyang Lake watershed, thus the relationship between pollutant background contents and land use, soil and topography could not be reflected properly, which affected the precision and reliability of pollution load assessment in the watershed scale to some degree. Therefore, it is crucial for non-point source pollution assessment in the Poyang Lake watershed in the future through strengthening the fundamental research related to soil erosion and reducing evaluation model cumulative deviation.