[Objective] This thesis took the marsh in Lesser Khingan Mountains as the object, to research the component of activated carbon in soil after wetland was transformed to farmland, forests. This abandoned farmland, which is of great scientific significance to the further understanding on the dynamic change of activiated carbon in soil and the corresponding effects of global warming mechanism.[Methods] This research selected four different types of land use(natural marsh, drainaged wetlands, abandoned farmland, farmland) as the objects, based on field investigation and indoor analysis, making a comparison of the content changes and proportion relations among soil organic carbon(SOC), dissolved organic carbon(DOC), microbial biomass carbon(MBC), easily oxidized organic carbon(EOC), light fraction organic carbon(LFOC), particulate organic carbon(POC). This research made an analysis of the relationship between active componets of organic carbon in soil with the correlation analysis.[Results] The content of organic carbon decreases with the increasing depth of soil under different land use patterns. In general, on the soil profile, the content of SOC in natural marsh is greater than that in other land use patterns, while the difference among the other three patterns of land use is not significant(p > 0.05). Under the four different land use patterns, the content of activated carbon component all shows a decrease tendency with increasing of soil depth in the vertical distribution. Generally, the contents of activated carbon component in the four different types of land use patterns are natural marsh > drainage wetlands > abandoned farmland > farmland.The correlation between SOC and DOC, MBC, EOC, POC, LFOC in soil is significant(p < 0.05).There is a significant positive correlation between DOC and MBC in soil(p < 0.05).There is rather a significant positive correlation between LFOC and POC in soil(p < 0.05).The correlation between EOC and other activated carbon components is not significant.[Conclusion] There are effects on the component of activated carbon in soil under different patterns of land use in Lesser Khingan Mountains. Therefore, people should rationally develop the marsh in Lesser Khingan Mountains.