Abstract: In order to explore the relationship between the soil organic carbon(SOC)and litter quality, we extracted the variables which reflected the litter quality characteristics by principal component analysis and set up a regression model between the litter quality and the SOC based on the standard investigation and sample measurement data of Pinus massoniana plantation. The results showed that: ① The SOC density of stand at 0-100 cm soil depth was 39.76-85.85 t/hm², which increased with the stand age, it mean that the SOC of near-mature forest and mature forest were significantly higher than the young forest and middle-aged forest(P<0.05). The SOC content and average density of 10 cm thickness at each soil layer among different age groups decreased gradually with the increase of soil depth. ② The total existing amount of litter(including semi-decomposed and undecomposed layer)was 1.54-2.25 t/hm², which increased with the stand age. However,element contents of litter showed no obvious variation. The existing amount of litter and the N, P content of each age group at different decomposed layers all showed that the semi-decomposed layer were higher than the undecomposed, the C content and C/N ratio showed the opposite rule. The average C content and C/N ratio of undecomposed layer were significantly higher than that in the semi-decomposed(P<0.05), and the average N content in undecomposed layer was significantly lower than that in semi-decomposed(P<0.05), the average P content of different decomposed layers had no significant difference(P>0.05). ③ The analysis of multiple linear regression between SOC and litter quality showed that the principal component variables which reflected the litter quality of undecomposed layer had a significant correlation with the soil organic carbon density(P<0.05), C content and C/N ratio were negatively correlated with organic carbon density(P<0.05), which displayed that the soil organic carbon density increased rapidly with the decrease of C content and C/N ratio of undecomposed layer and the decomposition rate accelerated. Therefore, replanting broadleaf species or applying nitrogen fertilizer could promote the rapid decompostion of undecomposed layer.