The carbon sequestration function of plantation ecosystem plays a significant role to alleviate global climate change. We measured the biomass,carbon content,carbon storage and carbon partitioning of a 31 - year - old Larix principis - rupprechtii by field investigation and laboratory analysis on Mt. Taiyue,Shanxi,China. It was found that the biomass of the individual tree was closely related with the diameter at the breast height and tree height. The mean stand biomass was 166. 82t·hm~(-2),and the biomass of each layer was in order of tree layer ( 111. 95t·hm~(-2) ) > litter layer( 36. 67t·hm~(-2) ) > herb layer ( 17. 85t·hm~(-2) ) > shrub layer( 0. 35t· hm~(-2) ) . The average carbon content in each components of the plantation ecosystem was 0. 4846gC·g~(-1) in stem,0. 5030gC·g~(-1) in bark ,0. 4753g C·g~(-1) in brank ,0. 4732gC·g~(-1) in leaf ,0. 4563gC·g~(- 1) in root ,0. 4161gC·g~(-1) in shrub layer ,0. 2898gC·g~(-1) in herb layer,0. 0176gC·g~(-1) in soil layer( 0 ~ 60cm) . The carbon content gradually reduced with the increasing of soil depth. The total carbon storage of the plantation ecosystem was 178. 3t·hm~(-2),of which,the carbon storage of soil layer was 112. 97t·hm~(- 2),accounting for 63. 36% of the total as the biggest carbon library. The carbon storage of vegetation layer was 59. 07t·hm~(-2),accounting for 33. 13% of the total,and the each layer was in order of tree layer( 54. 06t·hm~(-2) ) > herb layer( 4. 85t· hm~(-2) ) > shrub layer( 0. 15t·hm~(-2) ) . The carbon storage of litter layer was 6. 26t·hm~(-2),accounting for 3. 51% of the total. The tree layer had an annual net productivity of 9. 21t·hm~(-2)·a~(-1),and its annual net carbon sequestration was 4. 38t·hm~(-2)·a~(-1) .