Based on the long-term field experiment (18 years) in Zunyi, Guizhou Province, the effects of three different fertilization modes (no fertilization, chemical fertilizer application alone, chemical fertilizer combined with organic fertilizer) under two cropping systems (tobacco-maize rotation and continuous tobacco cultivation) on soil organic carbon (SOC) components, enzyme activities and carbon pool management index (CPMI) were investigated. The aim of the study was to explore carbon transformations in tobacco soils and to provide scientific management strategies for soil carbon. The results showed that, under the same cropping system, chemical fertilizer combined with organic fertilizer increased total SOC content by 5.65%~12.13%. Among them, light fraction organic carbon, dissolved organic carbon, and labile organic carbon increased by 23.33%~28.71%, 24.46%~25.54%, and 10.26%~18.99%, respectively. The CPMI also increased by 12.89%~23.34%. Soil cellulase, β-glucosidase, amylase, peroxidase, and invertase activities were significantly enhanced and were positively correlated with SOC components and carbon pool management index (0.59*~0.97**, n=18). Under the same fertilization conditions, SOC content, enzyme activities, and CPMI in the rotation were 6.14%~23.51%, 9.00%~37.92%, and 4.74%~14.44% higher than that in the continuous cropping system. In conclusion, tobacco-maize rotation with organic plus inorganic fertilizer application not only significantly increased SOC and CPMI, but also enhanced soil microbial biomass and active organic carbon, which is of great importance for improving soil fertility and sustaining soil productivity.