Abstract:In order to understand the causes of water pollution in the upper reaches of Zhanghe River, 11 rainfall monitoring were conducted on different underlying surfaces of typical functional areas in Changzhi City in 2017, and the event mean concentration(EMC)of pollutants in the runoff of each rainfall was analyzed. The annual non-point source pollution load of each city in the upper reaches of Zhanghe River in 2017 was estimated by the average concentration model method, and the pollution degree of each city and county was analyzed by using ArcGIS technology. The results show that in 2017, the non-point source pollution of rainfall runoff in Changzhi City is more serious. The EMC value of pavement runoff pollutants in each functional area is greater than that of roof, and the main pollution sources are SS, CODCr, TN and heavy metal Cd. The EMC value of SS of commercial area pavement is 666.87mg/L, that of Cd of industrial area roof is 44. 27 μg/L, and that of CODCr and TN of residential area pavement is 148.69 mg/L and 6.273mg/L, respectively. The total annual load of non-point source TN, TP, SS, CODCr, CD, Cu, Zn and Pb in the urban area of Changzhi City is 5.301t/a, 0.464t/a, 267.310t/a, 177.890t/a, 0.075t/a, 0.150t/a, 0.384t/a and 0.023t/a, respectively. The contribution rate of non-point source pollution annual load on three kinds of underlying surface to the river is in the order from large to small of roof, pavement and green space. In terms of spatial distribution, Changzhi City has the most pollution output and Wuxiang County has the least.