Land use types are important factor affecting soil organic carbon pool by regulating carbon fluxes between the terrestrial biosphere and atmosphere. Five typical land use types including farmland, grassland, shrubland, artificial forest and natural forest were selected to explore the responses of soil organic carbon pool to land use types and environmental factors in the karst faulted basin, China. The contents, stocks and distribution ratios of soil organic carbon (SOC) and labile organic carbon (LOC), namely dissolve organic carbon (DOC), easily oxidated carbon (EOC) and microbial biomass carbon (MBC), were analyzed along soil profiles (0-60 cm) under different land use types. The results showed that the SOC contents was 4.83-69.01 g/kg, which decreased with soil depths under the five land use types. The SOC stocks under five land use types were in descending order of shrubland (191.77 t/hm²), grassland (166.86 t/hm²), farmland (142.47 t/hm²), artificial forest (134.31 t/hm²) and natural forest (102.62 t/hm²). The contents and stocks of EOC and MBC were the highest in grassland and shrubland on average, followed by artificial forest and natural forest. The variation characteristics of EOC and MBC in the soil profile were consistent with SOC, but the decline rates of EOC and MBC contents in soil layers were obviously higher than SOC. Land use types and soil depths had no significant effects on DOC contents with a range of 0.84-1.62 g/kg under the five land use types. The ratios of labile organic carbon to soil organic carbon were affected by land use types and soil depths (P<0.01). The EOC/SOC and MBC/SOC ratios of artificial forest were lower than those of grassland, shrubland and natural forest. Pearson correlation analysis showed that SOC was positively correlated with LOC (P<0.01). In addition, SOC and LOC were positively correlated with total nitrogen, C/P ratio, C/N ratio, exchangeable calcium, soil water content, clay, sand and so on (P<0.05). Path analysis further identified that the variation in the SOC and EOC were significantly related to the changes of C/P ratio, total phosphorus, sand and exchangeable calcium and MBC was mainly influenced by sand and C/P ratio. These findings suggested that the land use types had significant effects on SOC, EOC and MBC contents and the responses of EOC and MBC to land use types were more sensitive than SOC in karst faulted basins. Moreover, more attention should be paid to soil physical structure and phosphorus availability in the future research on soil organic carbon pool.