Soil nitrogen is not only an essential nutrient element for crops, but also an important ecological element. The study on spatial variability of soil total nitrogen content at different scales is the basis for evaluating soil quality and predicting nitrogen storage in soil accurately. Based on the data of 1 041 soil profiles obtained during the second soil survey in Northeast China, three scales were set in this study, namely, administration region scale (county, city, province and region), soil taxonomy scale (family, sub-group, great group and order of soil) and soil type- administration scale (zonal soil and intrazonal and azonal soil), to study variability of soil total nitrogen (STN) content in the surface soil layer (0~20 cm) and the soil profile (0~100 cm) and its response to expansion of upland in scale. Results show that variability of STN content in the surface layer and in the profile increased with the expansion of scale. At the administration scale, a strong logarithmic relationship was found between the area of uplands or of the administrative region and the mean CV of STN content. At the taxonomy scale, though the mean CV of STN content of each soil order increased with the extension of scale from family to order, amplitude of the variation varied. At the soil type-administration region scale, zonal, intrazonal and azonal soils displayed a similar trend in variability of STN content, but differed in variation rate, and a strong logarithmic relationship between the area of uplands and the mean CV of intrazonal and azonal STN content was observed. These findings may provide a basis for assessing soil nitrogen storage in uplands clustered by soil type at various scales in Northeast China, and some theoretical guidance for determining the number of soil samples to be taken in investigation of soil resources in that region.