Background Soil is an important part of terrestrial ecosystem and the main storage and exchange pool in the process of global carbon cycle. The small changes of soil organic carbon will be further fed back into the global carbon balance and the maintenance of soil organic matter. Elevation is one of the important factors affecting the soil organic carbon pool, but there were many uncertainties in the related research, and there was still a lack of general understanding. The effect of carbon dynamics is of great significance on soil organic matter retention, soil aggregate structure stability, and soil and water conservation effects.

Methods The authors mainly summarized the advances of soil organic carbon pool components and carbon mineralization characteristics at different altitude gradients in eastern China. When the literatures were searched, the keywords included "altitude", "soil organic carbon", etc. The literatures were related to the soil organic carbon pool at different altitudes and the reasons for its dynamic changes. Furthermore, main conclusions were summarized and relevant data were extracted for more in-depth analysis.

Results The process of input and output of soil organic carbon had significantly impact on the soil organic carbon content. The differences in soil organic carbon content, organic carbon chemical composition, and soil organic carbon mineralization degree were all related to the change of altitude to a certain extent. Altitude gradient variation directly or indirectly caused the changes of soil types, soil enzymes, vegetation types, soil temperature, humidity and other environmental factors. Among them, the degree of fit between vegetation types, soil enzymes, temperature and soil organic carbon at different altitudes were relatively low, indicating the complexity of the interaction among them and soil organic carbon. Soil organic carbon was significantly related with soil water content (R²=0.409, P < 0.01), soil microorganisms (R²=0.217, P < 0.05), and soil type (R²=0.241, P < 0.01).

Conclusions 1) The content of soil organic carbon was positively correlated with the altitude (R²=0.174, P < 0.01), and the differences in the chemical composition of organic carbon and the degree of mineralization of soil organic carbon were related to the change of altitude to a certain extent; Under the condition of altitude, the organic carbon content of the upper soil was higher than that of the lower soil. 2) The degree of soil organic carbon mineralization increases with the elevation. In different soil layers at the same altitude, the soil carbon mineralization rate decreases with the deepening of the soil layer. 3) Under different altitude conditions, soil water content, soil microorganisms, and soil types are the main factors affecting soil organic carbon pool.