Abstract: On the basis of the sixth forest resources investigation report of Inner Mongolia,we calculated the change of forest carbon storage in Inner Mongolia by using dominant tree species investigation data. The results showed that the total forest carbon storage in Inner Mongolia was 748 million ton(Mt), about 9.59% of the total carbon storage of China forest resources within the corresponding period. The average carbon density of the dominant tree species was 28.73t/hm².At the same time,the difference in carbon fixation capacity of the dominant tree species was significant. Among them the carbon fixation capacity of broadleaf mixed forest was 80.98t/hm²., that of Pinus sylvestris var.mongolica was 67.44t/hm². and Betula platyphylla Suk was 49.13t/hm² respectively. The dominant tree species with the carbon fixation capacity over 40 tons perhectare were Picea 45.16t/hm², Larix 44.69t/hm², conifer-broadleaf mixed forest 44.15t/hm² and Quercus 40.37t/hm² respectively. The species with the carbon fixation capacity of less than 10t/hm² were Sophora japonicai 7.78t/hm², Ulmus 7.32t/hm², Malus baccata Borkh 5.7t/hm² and Tilia 4.36t/hm² respectively.

Key words: carbon storage, dominant tree species, carbon density, Inner Mongolia