This study was conducted in Taihe County,a degraded red soil region in Jiangxi Province.It focused on how plantation type and season affect the contents of soil labile organic carbon (SLOC).The contents of SLOC under pure forest of Pinus elliottii (Ⅰ),pure forest of Pinus massoniana (Ⅱ),mixed forest of P.elliottii-L.formosana (Ⅲ) and pure forest of Liquidambar formosana (Ⅳ),which were all built in 1991 were determined.The results showed that the contents of dissolved organic carbon (DOC),readily oxidizable organic carbon (ROC),and microbial biomass carbon (MBC) were in the ranges of 52.67~105.17,6.68~13.33 and 57.70~154.21 mg/ kg,respectively.It was found that DOC decreased in the following order of Ⅳ > Ⅲ > Ⅱ Ⅰ,and the decreasing order of MBC and ROC was Ⅳ Ⅲ > Ⅱ Ⅰ.The contents of DOC,ROC and MBC with substantial seasonal fluctuations under different plantations were also observed.The soil DOC,MBC and ROC under the four plantations tended to be higher in summer and autumn than in spring and winter,which may be attributed to the climatic factors such as temperature and precipitation.