[Objective] To analyze the export characteristics and source of non-point source in order to provide reference basis for the study of the similar agricultural watershed water quality and non-point source pollution control.[Methods] This area was firstly divided into certain catchments with ArcGIS software. The water quality and precipitation was monitored across sections in 2014. Combined with the mean concentration method and export coefficient model, a calculation model was set up to estimate non-point source pollution export, and the sources for various non-point pollutants was analyzed with optimized mathematic method.[Results] The total nitrogen export coefficients of agricultural land, woodland, residential land, domestics and livestock was 15.87 kg/(hm²·a), 6.33 kg/(hm²·a), 6.27 kg/(hm²·a), 0.20 kg/(person·a), 0.83 kg/(anamal·a), respectively, while the total phosphorus export coefficients was 0.46 kg/(hm²·a), 0.39 kg/(hm²·a), 0.67 kg/(hm²·a), 0.10 kg/(person·a), 0.16 kg/(anamal·a), respectively. Nitrate nitrogen was the main form of nitrogen loss in the runoff and a large amount of particulate phosphorus run off in the periods of peak rainfall. In the precipitation, ammonia nitrogen and dissolved phosphorus was main loss form.[Conclusion] In this small catchment, precipitation, woodland and domestic waste are the main pollution sources.