Abstract: Abstract：The water quality of Danjiangkou reservoir is good on the whole, but the problem of excessive total nitrogen is prominent. To clarify the distribution and output characteristics of nitrogen in different types of small watershed, and optimize the formulation of nitrogen control measures in the reservoir area, typical watershed around the reservoir was selected to carry out observation and analysis of nitrogen concentration in water. The results showed: (1) The average total nitrogen content in Yujiawan (hoggery type) was 21.23 mg/L, and that in Wulongchi (village type) was 4.00 mg/L, higher than that in Qianjiagou (natural type) and Zhanggou (farmland type). Wulongchi had the highest nitrate nitrogen, with an average of 2.37 mg/L, while Zhanggou had the lowest, with an average of 1.06 mg/L. The content of ammonia nitrogen in Yujiawan is much higher than that in Qianjiagou and Zhanggou. (2) The downward trend of ammonia nitrogen along Qianjiagou was significant (p<0.05), and the nitrate nitrogen (p<0.01) and total nitrogen (p<0.01) increased significantly in Zhanggou. The micro-topographic structure such as the pit wetland may be the main factor affecting the nitrogen change along the small watershed. (3) The concentration of nitrogen in Qianjiagou and Wulongchi was higher in winter (from December to February), lower in summer and autumn (from June to November), and fluctuated the most in spring (from March to May). The high value of nitrogen in Zhanggou appeared in June, while the high value of nitrogen concentration in Yujiawan appeared in August. (4) In Yujiawan, ammonia nitrogen was the main nitrogen. In Wulongchi, Zhanggou and Qianjiagou, nitrate nitrogen dominated. Based on the above conclusions, the distribution and quantity of different types of small watershed should be systematically sorted out for subsequent nitrogen control in danjiangkou reservoir area, with the emphasis on ammonia nitrogen pollution in hoggery type small watershed and nitrate nitrogen pollution in village type small watershed.