Abstract:Using continuous and distributed mechanism model of AnnAGNPS (annual agricultural non-point source model), the non-point source pollution was simulated at Sihe watershed in Tan-River basin of the Pearl River delta. The temporal and spatial distribution characteristics of suspending sediment (SS), total nitrogen (TN), and total phosphorus (TP) was analysed. Model adaptability using in Sihe watershed was proved by coefficient of determination(R2)and Nash Sufficient. Both of them were larger than 0.8 between calibrated period and validated period. The results showed that 80% amounts of pollution were generated from April to September, simultaneously with rain. TN and TP had similar spatial distribution characteristics in the study area,and the pollution loadings of NPS were higher in the middle and downstream area than in the north-eastern and north-western regions.