The soil organic carbon (SOC) pool is an important component of global carbon stock, It could play a huge impact on global terrestrial carbon cycling, eco-system construction and material recycling due to its slight changes. Plant diversity could influence the temperature, humidity, microorganisms and litter of forest floor, and then affect the reserves of SOC. The hilly region in central Sichuan province is a critical part of ecological barriers in the upper reaches of the Yangtze River, and the low efficiency stands of Cuprssus funebris grow in these areas are the main forest types. Our objectives were (1) to explore the characteristics of SOC in the low efficiency stands of Cuprssus funebris which have been reconstructed for 10 years, (2) to quantify the relationships between SOC and plant diversity of the tree layers, the shrub layers and the herb layers.The planting patterns of Bambusa pervariabilis×Dendrocalamopsis daii (CZ), Cupressus funebris Endl.+Bambusa pervariabilis×Alnus cremastogyne Burk.+ Alnus cremastogyne Burk. (BZQ), Cupressus funebris Endl.+Quercus acutissima Carruth (BL), Cupressus funebris Endl.+Bambusa pervariabilis× Dendrocalamopsis daii (BZ) were reconstructed in 2002. CZ pattern was reconstructed on the planting spacing of 4 m×4 m after clear cutting, and the other patterns were reconstructed by interplanting after intermediate cutting. In 2012, 3 sample plots were set in each pattern to study SOC content, SOC density, easily-oxidized carbon (EOC), water-soluble organic carbon (WSOC), soil microbial biomass carbon (SMBC) and plant diversity. The results were found as follows: (1) The contents of SOC and its components were decreased with increasing soil depth, with the maximal drop of SOC and the minimum drop of EOC; SOC density in topsoil (0-10 cm) accounted for 45.7% to 64.4% of the whole sampling profile, exhibiting obvious surface accumulation. (2) SOC content, SOC density, EOC, WSOC and SMBC content in 0-40 cm were in the order of BZQ > BZ > CB > BL > CZ, with significant differences (P < 0.05). Compared with CB, the increase rates of SOC content, SOC density, EOC, WSOC and SMBC content were 37.8%, 33.5%, 36.6%, 52.5% and 23.2%, respectively, and BZQ revealed the most obvious effect on SOC. (3) The index of species dominance, species diversity, species evenness and species richness were roughly arranged as BZQ > BZ > CB > BL > CZ. There were significant positive correlation between SOC content, SOC density, EOC, WSOC and SMBC content and the plant diversity of shrub and herbaceous layers, while the correlation were not significant between SOC and its components and the plant diversity of tree layer. It indicated that the effects of the diversity of herbaceous and shrub layers on SOC were more obvious than those of the other tree layers. The most obvious influence on the improvement of SOC content was BZQ pattern, and thus this pattern was proposed to promote. Due to the vegetational transformation in the studied region is still in its initial stage, vegetation succession will continue and in a unstable state, therefore, it will be more meaningful to provide a theoretical basis for the transformation of low efficiency stands of Cupressus funebris.