Forest carbon storage usually increases with stand age. Most studies focus on the carbon storage of arbor layer, however there are few in-depth studies on the allocations for different layers of community varying with stand age. In this paper, biomass has been estimated and carbon storage and immobilization at different ages in Larix olgensis plantation have been studied, based on the survey of sample plots in Larix olgensis plantation ranging from 7 to 41 years in representative region of Lesser Khingan Mountains ( Northeast of China ). The methods of allometric dimension analysis and sampling harvest (quadrat or transect sampling method from Forest Inventory and Monitoring, US) were used to investigate the biomass of arbor layer, understory vegetation layer and down woody materials (DWM) layer. Carbon content in different organs of Larix olgensis were determined using an ELEMENTAR Vario EL Ⅲ CN Analyzer. The main results are as follows: (1) The biomass of both arbor layer and organs along with the proportion of stem increased significantly with stand age. For understory vegetation layer and DWM layers, the biomass changed in the same tendency. Fitness of the equations for arbor layer was good, and the change of parameters, such as biomass expansion factor (BEF) and root/shoot ratio (R) were in normal level. For example, the value of R was high in early age and then gradually tended to a steady state. (2) Total carbon storage of community increased with stand age, and is in sequence of arbor, DWM, and understory. At different vegetative stages carbon storage were 6.585 t?hm-2,66.934 t?hm-2,90019 t?hm-2,124.603 t?hm-2,162.683 t?hm-2, for immature, juvenile, middle-aged, near-mature and mature stand respectively. For carbon storage of arbor layer were 3254 t?hm-2,58.521 t?hm-2,78.086 t?hm-2,108.02 t?hm-2,138.096 t?hm-2. Mean carbon storage of understory and DWM layers were 10859 t hm-2 and 1.863 t?hm-2. The proportions of arbor, DWM and understory layers were 86.10%, 2.04% and 11.86%, differences among the ages became littler gradually with the augmentation in stand age. (3) The dynamic trend of carbon immobilization in different stages enhanced at the very beginning, and then declined. The accumulation rate of carbon storage in middle-aged stand was higher than those at other stages. Carbon immobilization of community were 0940 t?hm-2,3.889 t?hm-2,3.615 t?hm-2,3.628 t?hm-2,3.968 t?hm-2, and that of arbor layer were 0465 t?hm-2,3.39 t?hm-2,3.137 t?hm-2,3.133 t?hm-2,3.368 t?hm-2.With the trend appearing as U-shaped line, immobilization in understory layer had a decreasing duration(from 7 a to 19 a) while DWM layer was going up linearly. The mean immobilization for understory and DWM layers were 0079t?hm-2 and 0423t?hm-2. In conclusion, our study shows that carbon storage and distribution patterns in Larix olgensis plantation expressed obvious dynamic variations with stand age. We expected that our in-depth analysis can provide insight into the methods for estimating carbon storage and dynamic change laws in forest community at different ages. It can also be concluded that Larix olgensis plantations as an important and widely distributed plantations over northeast China, have huge carbon storage potential in the future.