Soil is a major terrestrial carbon pool and most of the soil carbon is stored in the deep soil layers, which contributes to more than half of the total soil carbon storage. Compared with the topsoil carbon storage, carbon reserved in deep soil depth may respond differently to environmental change and land management practices. Thus, it needs to consider the deep soil organic carbon storage in the global carbon cycles. In the subtropical hilly region of China, some soils are deeply weathered and have highly developed profile. These deeply weathered soils may very sensitive to land use changes. Until recently, the dynamics of carbon storage in deep soil, especially its response to land use conversion was largely ignored in the subtropical hilly region of China. In the present study, soil carbon storage at 1 m depth, soil δ¹³C value and fine root biomass were evaluated within a representative land-use sequence in mid-subtropical China. The purpose was to evaluate the effect of land use change on the storage and resource of deep soil carbon storage. The land-use tpes included natural forest (control treatment), Chinese fir plantation, Chinese chestnut orchard and sloping tillage. Results showed that soil carbon storage at 1 m depth was 112.03, 82.40, 78.83 and 72.29 t/hm² for natural forest, Chinese fir plantation, Chinese chestnut orchard and sloping tillage, respectively. After the natural forest was converted to other land uses for 7 years, soil carbon storage was decreased by 26%-36% at 1 m depth. Not only the topsoil (27%-34%), but also the deep soil (below 40 cm) showed significant decrease of carbon storage by 19%-45%. The conversion from natural forest to sloping tillage exerted a larger decrease of soil carbon storage than to Chinese fir plantation and Chinese chestnut orchard. In contrast to the decrease of soil carbon storage with land use changes, the average δ¹³C value at 1 m depth was increased by 1‰-3‰, indicating an increasing contribution of carbon input from C₄ plant species to soil. After the land-use conversion, severe human disturbance caused serious topsoil erosion and water loss and shift of plant species composition. This led to the reduction of carbon input to soil and the increment of carbon loss in deep soil, and further to a substantial decrease of deep soil carbon storage. In addition, the fine root biomass at 60 cm depth was reduced by 50%-99% and tended to concentrate in surface soil layer after the land-use changes. It was primarily due to the deterioration of soil physicochemical regime, decrease of available soil resource and juvenile vegetation after the land use conversion. The decrease of fine root biomass also reflected a substantial degradation of land productivity. In conclusion, our study raises concerns about (i) the importance of natural forest preservation and young forest nurture; (ii) innovation of agronomic soil practices as regarding to topsoil disturbance reduction and continue implementation of "grain for green" policy in sloping tillage; and (iii) controlling of topsoil erosion and water loss and supplement of chemical fertilizer after the land-use conversion in hilly region of middle subtropical China.