To study evolution of the characteristics of the soil organic carbon pool in the Karst region of Maolan with the process of natural restoration of karst forest vegetation, the concept of space as a substitute for time was adopted. Results show that soil bulk density (0.94~1.15 g cm^-3 in 0~10 cm soil layer and 0.98~1.19 g cm^-3 in >30 cm soil layer) and rock fragment content (19.93~26.61% in 0~10 cm soil layer and 20.36~32.11% in >30 cm soil layer) increased with soil depth and decreased along with the process of the restoration; soil volume (20.13~22.02 m³ in 0~10 cm soil layer and 4.16~6.87 m³ in >30 cm soil layer), soil organic carbon content (21.14~52.67 g kg^-1 in 0~10 cm soil layer and 11.15~25.93 g kg^-1 in >30 cm soil layer), soil organic carbon density (1.91~4.03 kg m^-2 in 0~10 cm soil layer and 0.39~1.96 kg m^-2 in >30 cm soil layer), soil organic carbon storage (0.538~0. 883 t in 0~10 cm soil layer and 0.039~0.137 t in >30 cm soil layer in a sample lot 900 m² in area) and readily oxidizable carbon (5.28~33.25 g kg^-1 in 0~10 cm soil layer and 5.98~14.13 g kg^-1 in >30 cm soil layer) increased with the process of the restoration and decreased with soil depth; soil organic carbon became more stable and less active with the process of the natural restoration in the 0~20 cm soil layer, but went reversely in the >20 cm soil layer and it increased in stability and decreased in activity with soil depth. The variation of soil organic carbon with the process of the natural restoration generally demonstrates that soil plays a role as a sink of atmospheric carbon dioxide. At the early restoration stages, soil organic carbon in the soil was low in quantity, poor in quality, and high in surface accumulation tendency, showing that the sink effect of the soil was not significant and that the soil was high in carbon sequestration potential, however, at the late stages, all went reversely. It is, therefore, essential to take strong measures to preserve karst forests and let them restore naturally, which helps improve soil quality and accumulate organic carbon.