Abstract: In order to identify the priority management area of nonpoint source pollution in the Zuli River basin, the Zuli River basin, a firstclass tributary of the Yellow River, was selected as the research object based on the SWAT model. The study firstly simulated the spatial distribution of total nitrogen loads from nonpoint sources in the basin, and analyzed the change of total nitrogen loads in the basin from the perspective of the interannual and inter-monthly changes. The upstream and downstream relationships in the sub-basins and the role of the river channel in retaining the pollutants were considered. The Yellow River confluence in the basin is the water quality impact monitoring point.Based on the total nitrogen pollution intensity of the sub-basins relative to the entire basin, non-point source pollution priority management area were divided. The results show that the SWAT model is applicable in the Zuli River basin, and the Nash efficiency coefficients are higher than 0.5 using SWAT-CUP software for the simulation values of runoff and water quality for parameter rate fixing.From the simulation results, it can be concluded that there is a large difference in total nitrogen loads in each sub-basin, and the total nitrogen loads of the sub-basins located in the upper reaches of the basin are small, and those sub-basins with large loads are mainly distributed in the outlet of the river.From 2001 to 2022, the trend of total nitrogen load in the whole watershed was approximately the same as that of annual precipitation; and the seasonal change was obvious, with the highest total nitrogen load in summer. According to the intensity of total nitrogen pollution, the sub-basins were divided into three types of pollution priority management zones, and it was found that the sub-basins that need to prioritize the management of non-point source pollution during the 20-year period were distributed along the main channel of the Bitter Water River, which is the upper reaches of the Zu Li River, from the south to the north. The results can provide a reference for the management of nonpoint source pollution and ecological restoration and protection in the Zuli River basin.