The decomposition and organic carbon release characteristics of litters of Abies georgei var. smithii and Picea likiangensis var. linzhiensis in two typical dark coniferous forests in southeastern Tibet were studied by combining the method of litter decomposition bag and laboratory analysis, the relationship between organic carbon release rate and soil organic carbon and its components in two subalpine dark coniferous forests was analyzed, the results showed that the decomposition of litters in the two original dark coniferous forests in southeastern Tibet showed the characteristics of fast decomposition in rainy season (April to September), slow decomposition in dry season (October to march), fast decomposition in early stage (march to September) and slow decomposition in late stage (October to February). The decomposition rate of fir (PLLF) was higher than that of spruce (AGSF). Olson exponential decay model could well model the decomposition of litter in two dark coniferous forests. The half-decomposition time of litter in fir (PLLF) and spruce (AGSF) were 2.11 and 2.52 years. The 95% of decomposition time were 8.96 and 10.84 years. The organic carbon content in the litters of the two dark coniferous forests showed a trend of first rising, then falling, and then steadily declining, while the release rate of organic carbon in the litters showed a pattern of first brief enrichment and then release. The contents of total organic carbon (TOC) and its active components (MBC, POC and LOC) in the soil of the two dark coniferous forests were obviously surficial (p<0.01), and the contents of TOC, MBC, POC and LOC in the same soil layer were significantly positively correlated with each other (p<0.01). There was a significant positive correlation between the release rate of organic carbon in the decomposition process of litters of the two dark coniferous forests and the contents of TOC, MBC, POC and LOC in the topsoil (0-10 cm), TOC and MBC in the soil layer of 10—20 cm and MBC in the soil layer of 20—40 cm (p<0.05).