This research was conducted in Huanghuadianzi watershed in Aohan of Chifeng city, Inner Mongolia. The Geo-statistical and ArcGIS spatial analysis techniques were used to study the spatial variations of soil organic carbon density (SOCD) at the different scales. The results disclosed the obvious scale-dependency of SOCD spatial variability. The rate of nugget to sill was reduced with the increase of the scale. SOCD showed moderate spatial correlation at small scale but showed strong spatial correlation at large and middle scale. Structural?factors on SOC spatial variability?increased gradually, while weakened the?influence of random factors?on SOCD variation.?Terrain?factor and NDVI?had significant effects on?SOCD, at large?scale,?the correlation between environment?factors and SOCD?ranked as?altitude?>?slope?>?NDVI?>?slope aspect, while at meso- scales and small-scales the influence of environment factors showed NDVI?>?altitude?>?slope > slope aspect.