Abstract: To solve the environmental problems caused by excessive cultivation, application of fertilizer and pesticide in Guanxi pomelo orchard of Pinghe, we investigated the runoff N and P content under different fertilizations by field investigation and indoor analysis in mountain orchards of Pinghe. The results showed that: the content of runoff N (total nitrogen, soluble nitrogen, nitrate nitrogen, ammonia nitrogen) and P (total phosphorus and soluble phosphorus) decreased, and was greater than the catchment content of different experimental zones respectively (hilly pond, ditch, stream and Jiulong river); (2) garden runoff N/P was greater than 6.5, phosphorus content was the limiting factor of eutrophication; nitrate content in orchard runoff was lower than the content restriction for drinking water (10 mg/L); (3) the yearly total phosphorus content of experimental zone catchment was 0.403, 0.280, 0.503, 0.417 mg/L, respectively, basically higher than Ⅲ class water quality requirements (0.3 mg/L); the annual ammonia nitrogen content was 0.14, 0.20, 0.44, 0.10 mg/L, respectively, which achieved Ⅱ class water quality requirements; the total nitrogen content was 3.77, 3.49, 3.89, 3.38 mg/L, respectively, all higher than Ⅴ class water quality requirements of 2.0 mg/L. In general, orchard runoff can not meet the surface water environmental quality standards, and direct discharge will produce water eutrophication.