Abstract: To investigate the spatial distribution and pollution characteristics of nitrogen and phosphorus in the water and surface sediments of the Nansi Lake watershed, the concentrations of total nitrogen (TN) and total phosphorus (TP) in the water and surface sediments of the lake and the lake's 53 inlets, were measured, and their distribution and pollution characteristics were analyzed. The results indicate that the water quality in the Nansi Lake area is classified as Class Ⅲ and the water quality gradually improves from north to south. The average TN and TP concentrations in the surface sediments of the lake were 2 071 and 623 mg·kg^-1, respectively. The average TN and TP concentrations of the surface sediments of lake's inlets were 1 765 and 608 mg·kg^-1, respectively. The TN concentration in the lake sediments is significantly higher than that in the lake's inlet sediments (P < 0.001), while the difference in their TP concentrations is not statistically significant. The results of sediment pollution evaluation in the Nansi Lake show that the values of TN pollution index (S_TN), TP pollution index (S_TP), and comprehensive pollution index (FF) in the lake are 1.86, 1.39, and 1.74, respectively, indicating moderate pollution. The sediment pollution in different sections of the lake varies greatly, and the TN and TP in the Dushan Lake section and the TN in the Weishan Lake section have reached to the level classified as heavily polluted, implying a looming threat of eutrophication.