The allocation pattern of carbon storage in forest ecosystems significantly affects the terrestrial carbon budget,but such pattern is unclear in the Chinese fir plantations in Hunan Province. On the basis of the field investigation of sample plots in Hunan Province and the data of the Eighth National Forest Inventory,we calculated the carbon storage and density of Chinese fir plantation ecosystems in Hunan Province. The results showed that the carbon density of Chinese fir plantation ecosystems increased with the increasing stand age. The ecosystem carbon densities of young,middle-aged and mature plantations were 125.70,138.57 and 193.72 Mg·hm~(-2),respectively. The vegetation carbon densities of young,middle-aged and mature plantations were 18.72,38.86 and 62.48 Mg·hm~(-2),respectively. The soil carbon densities of young,middleaged and mature plantations were 105.49,97.23 and 126.70 Mg·hm~(-2),respectively. The total carbon storage of Chinese fir plantation ecosystem was 307.48 Tg,of which,the carbon storage in young,middle-aged and mature plantations was 90.57,91.87 and 125.1 Tg,respectively. The carbon sequestration potential of Chinese fir plantation ecosystem was 85.56 Tg,of which the carbon sequestration potentials of vegetation and soil were 47.19 and 34.82 Tg,respectively. Quantifying the potential of plantation carbon sequestration can help evaluate the maximum carbon sequestration capacity and design sustainable forest management strategies for achieving its potential in mitigating climate change.