The contents of soil organic carbon and its components in six different forest types (including broad-leaved forest, coniferous forest, spruce-fir forest, betula ermanii forest, betula ermanii-tundra transition and tundra) on the northern slope of Changbai Mountain were studied by means of field sampling and laboratory analysis. The distribution of soil organic carbon, iron-aluminum oxides and clay mineral groups were analyzed. The results showed that in different forest types, the contents of organic carbon, humin carbon, particulate organic carbon, 2~0.25 mm macroaggregate carbon and 0.25~0.053 mm microaggregate carbon in broadleaf forest soils were the highest. The content of easily oxidized carbon in soil of spruce-fir forest was the highest while that of water-soluble organic carbon, humic acid carbon, fulvic acid carbon and particulate organic carbon were the lowest. In addition, the contents of humic acid carbon and fulvic acid carbon in the soil of betula ermanii forest were significantly higher than those of other forest types. The content of water-soluble organic carbon in the soil of betula ermanii-tundra transition were significantly higher than those of other forest types, while the contents of organic carbon and easily oxidized carbon in the soil of tundra were significantly lower than those of other forest types. Correlation analysis showed that soil organic carbon contents were positively correlated with amorphous alumina contents (P<0.05), fulvic acid carbon contents were positively correlated with free alumina contents (P<0.05), and organic carbon contents of 0.25~0.053 mm microaggregate were positively correlated with the contents of two kinds of alumina (P<0.05). These results indicated that the significant differences in organic carbon and its components were observed under different forest types.