Soil light fraction organic carbon (LFOC) is regarded as one of the most sensitive indexes of soil labile carbon because the content and turnover ratio is more readily influenced by recent land use and environmental changes than the total organic carbon of soil. The subalpine forest soil in the southwestern China is one vulnerable ecosystem with high altitude and low temperature. The dynamics of LFOC in 0-10cm and 10-20cm soil with and without litter and/or snow cover of subalpine forest were assessed by on-site incubation of repacked homogenized soil during the cold season. The results showed that LFOC content was 15.5% of the total organic carbon in 0-20cm soil on average, and varied from 13.6% to 21.1% under different treatments with litter cover and/or snowcover after a cold season. Soil LFOC in 0-10cm layer under litter and snow cover was lower than those of other treatment, which indicated that soil surface cover of litter and snow and their combination impacted LFOC content significantly, and the coexsitence of litter and snow was helpful to restrict LFOC formation and to maintain organic carbon stability during the cold season. Different temporal dynamics of LFOC content in 10-20cm layer also showed significant difference under different treatments, indicating that subsoil LFOC were also associated with surface cover. Soil LFOC content and fluctuation were rather high during the cold season, even higher than that in the growth season, which suggested that soil LFOC was active even during the cold season. Litter cover, snowcover, sampling time, soil depth and their interactions affected soil LFOC dynamics in cold season significantly. It was concluded that soil carbon pool size and its stabilization of subalpine forest in the southwestern China would be influenced significantly by the changes of litter and snow cover during the cold season, especially under the global warming and land use changes.