Rubber(Hevea brasiliensis) plantations have been expanded rapidly in tropical regions of Southwest China and cover more than20% of land area in Xishuangbanna.Several studies have addressed changes of soil C stocks in rubber plantations;however,estimates of total ecosystem C stocks and their temporal changes in rubber plantations have been inadequately studied.This study calculated C stocks in soil,biomass,litter,and dry rubber(latex),and estimated the total ecosystem C stocks of rubber plantations in an age sequence of 3-,7-,9-,21-,27-,and 34-year-old in Xishuangbanna,Southwest China.The total C stocks in rubber plantations ranged from 150.3 to 283.7 Mg C ha~(-1),with a mean of 213.4 Mg C ha~(-1).The plantations≤9-year-old had significantly lower(P<0.05)total C stocks than those older than 9 years.Carbon stocks in soil(mass equivalent) were between 107.1–170.5 Mg C ha~(-1) and in living biomass were between 2.8–95.7 Mg C ha~(-1),representing the largest and the second largest C components in a rubber plantation ecosystem.Neglect of dry rubber C stock resulted in an underestimate of 7.8%–14.2% of the total C stock in the rubber plantations older than 9 years,which was much larger than the contribution of litter C stock(less than 2%). Rubber (Hevea brasiliensis) plantations have been expanded rapidly in tropical regions of Southwest China and cover more than 20% of land area in Xishuangbanna. Several studies have addressed changes in soil C stocks in rubber plantations; however, estimates of total ecosystem C stocks and their temporal changes in rubber plantations have been inadequally studied. This study calculated C stocks in soil, biomass, litter, and dry rubber (latex), and estimated the total ecosystem C stocks of rubber plantations in an ancestral sequence of 3-, 7-, 9-, 21-, 27-, and 34-year-old in Xishuangbanna, Southwest China. The total C stocks in rubber plantations ranged from 150.3 to 283.7 Mg C ha -1 with a mean of 213.4 Mg C ha ~ (-1) .The plantations≤9-year-old had significantly lower (P <0.05) total C stocks than those older than 9 years.Carbon stocks in soil (mass equivalent) were between 107.1-170.5 Mg C ha ~ ( -1) and in living biomass were between 2.8-95.7 Mg C ha -1, representing the largest and the second largest C c omponents in a rubber plantation ecosystem. Neglect of dry rubber C stock resulted in an underestimate of 7.8% -14.2% of the total C stock in the rubber plantations older than 9 years, which was much larger than the contribution of litter C stock (less than 2%).