The characteristics of mineral nitrogen loss through surface flow and interflow in different types of vegetation in a water conservation forest were analyzed in the headstream of Taizi river. To explore the limiting factors which affect nitrogen loss, redundancy analysis and partial redundancy analysis were applied to study the relationship between nitrogen loss and environmental factors, and quantitative analysis was applied among the main influential factors. The results showed that nitrate nitrogen was the main form of nitrogen loss in both the surface flow and interflow. The concentration of nitrate nitrogen was 1.5 times more than the ammonium nitrogen in the surface flow and 20.5 times in the interflow. Whether in the surface flow or interflow, ammonium and nitrate concentrations were in the order of plantation forest > hardwood forest > secondary forest. Owing to the effects of surface flow and interflow, the amount of ammonium loss was the largest in secondary forest; the amount of nitrate loss was the largest in plantation forest. Soil physical and chemical properties were the main influential factors of the concentration of nitrogen loss, with their effects accounting for 46.36% and 16.42% of the total explanation, respectively. Geomorphology-hydrology factors and vegetation types were the main influential factors of the amount of nitrogen loss, with their effects accounting for 22.85% and 15.09% of the total explanation, respectively. The mixed effects of hydrological factors, vegetation characteristics, soil physical properties, soil chemical properties on nitrogen loss characteristics also played an important role, accounting for 36.03% and 51.36% of the total explanation for the concentration and the amount of nitrogen loss, respectively.