[Objective] The objective of this study is to analyze the spatial variability of soil nitrogen(total nitrogen, nitrate nitrogen and ammonium nitrogen) in Bailongjiang watershed in Gansu Province, and provide scientific basis for the management of soil nitrogen and the regulation of integrated ecosystem.[Methods] Soil samples were collected at a depth of 0-20 cm, and were tested in laboratory. Geostatistical methods combined with ArcGIS 10.2 were applied to analyze the spatial variability and distribution pattern of soil nitrogen.[Results] The variation coefficient of total nitrogen, nitrate nitrogen and ammonium nitrogen were moderate, with the value ranged from 35% to 90%. The rations of nugget to sill of total nitrogen, nitrate nitrogen and ammonium nitrogen were ranged from 50.13% to 63.19%, the spatial variability was affected by structural and random factors, and the best fitting theoretical semivariogram models of soil nitrogen were Gaussian models. As a whole, the spatial distribution of total nitrogen and nitrate nitrogen were higher in northwest but lower in southeast, and the soil ammonium nitrogen in the northwest area was lower than that in southeast.[Conclusion] The content of total nitrogen and nitrate nitrogen varied remarkably in different land use types and altitudes, while there was no significant correlation between ammonium nitrogen and different land use types and altitudes.