Abstract: The content, storage and distribution of carbon in 7yearold Acacia crassicarpa plantation ecosystem were studied. The results showed that carbon content in different organs of A.crassicarpa trees ranged from 470.1 g/kg to 533.8 g/kg, and decreased in the order of leaf>branch>stem>root>bark.The carbon content in shrub, herb and litter floor were 4654 g/kg, 425.7 g/kg and 478.3 g/kg, respectively. Carbon content in the soil (0—80 cm) was 12.94 g/kg and declines with soil depth. The total carbon storage in A.crassicarpa plantation ecosystems amounted to 141.05 t/hm2, of which overstorey of A.crassicarpa stored 46.97 t/hm2 and accounted for 33.30%, and understorey plant stored 2.07 t/hm2 and accounted for 1.47%, and litter floor stored 4.49 t/hm2 and accounted for 3.18%, and soil stored 92.01 t/hm2 and accounted for 65.23%. The carbon storage in different organs was positively related to the biomass of corresponding organs. Stem accumulated the highest carbon storage, comprised 52.20% of carbon storage in overstory trees, the rest in branch, leaf, bark and root, etc., seized 47.80%. The annual net productivity of 7yearold A.crassicarpa plantation was 20.06 t/(hm2·a) and annual carbon fixation was up to 9.86 t/(hm2·a).