Forests retain large amounts of organic carbon mainly through the accumulation of photosynthetic products and the sequestration of soil organic carbon. Plant litter transfers carbon from plants to soils as a more stable pool with high resistance time. Non-structural carbohydrates (NSC), such as soluble sugars and starch, are labile components in plant litter and could be released quickly from decomposing litter and utilized by soil microorganisms. Therefore, the NSC in plant litter could involve in soil biogeochemical cycles and is a key driver for carbon and nutrient cycling in forest soils. In this study, we collected monthly fresh leaf and twig litters of Castanopsis carlesii (a dominant tree species in subtropical evergreen broad-leaved forest), Cunninghamia lanceolata and Pinus massoniana (two main planted trees in subtropical China) in a natural Castanopsis carlesii forest and the Cunninghamia lanceolata and Pinus massoniana plantations over one year to assess the seasonal dynamics of the NSC (including soluble sugars and starch) in fresh litters. The results showed that the NSC content in fresh litter varied significantly among seasons for all studied litter species and between litter types (leaf versus twig). In general, the NSC content in the leaf and twig litters of Castanopsis carlesii, Cunninghamia lanceolate, and Pinus massoniana greatly increased in November and December but decreased dramatically from February to June of the following year. The NSC content differed significantly between litter types:the NSC content in leaf litters of Castanopsis carlesii, Cunninghamia lanceolata and Pinus massoniana showed average values of 3.03%-3.56%, 2.18%-4.37%, 3.38%-4.89%, respectively, while those in the twig litters were 1.87%-4.22%, 2.88%-4.28%, 2.75%-5.27%, for the three litter species, respectively. The NSC contents in leaf litters of Castanopsis carlesii and Pinus massoniana were generally higher than those in the twig litters, and the NSC content in twig litter of Cunninghamia lanceolata was higher than that in the leaf litter. The NSC content in fresh litter also varied significantly among tree species:the NSC contents in leaf litters of Castanopsis carlesii and Pinus massoniana were significantly higher than that of Cunninghamia lanceolata, and the NSC content in twig litter of Pinus massoniana was significantly higher than that of Castanopsis carlesii. The results suggest that the NSC content in fresh litter varied significantly between litter types, tree species and litterfall rhythms. The conversion of subtropical evergreen broad-leaved forests to Cunninghamia lanceolata and Pinus massoniana plantations may change the input of easily decomposable components from seasonal litterfall, and this change in labile carbon input from fresh litterfall may affect soil microbial turnover and microbially mediated biogeochemical cycles in forest soils of subtropical China.