The spatial variability of SOC content of 0–30 cm soil layer and the relationships with vegetation types, topography and soil characteristics in Tianlaochi Catchment in Qilian Mountains was analyzed by Kriging interpolation method and ANOVA. The results indicated that the average of SOC content was 83.05 g/kg, the coefficient of variation was 0.56. SOC had the significant vertical distribution, that is, SOC content decreased with increasing soil depth. The average SOC contents were 105.08, 81.46 and 62.62 g/kg in 0–10, 10–20 and 20–30 cm, respectively. The SOC contents under Qinghai Spruce, Shrub, Qilian Sabina, Subalpine meadow and Dry grasslands was 138.20, 118.49, 100.43, 74.17 and 43.94 g/kg in 0–10 cm, respectively. From 2 600 m to 3 600 m, SOC content increased with increasing altitude. SOC content was also different with the different slope aspect, the shady slope was higher than that in sunny slope. Correlation analysis showed that SOC content was positively correlated with total nitrogen and sand content, and negatively correlated with soil bulk density, clay and silt content.