Based on the data of 45 plantation stand plots(1 000 m²) with five different stand ages(1a,2a,3a,5a,and 8a) collected from 50 sample sites in the main eucalyptus production areas in Guangxi,southwest in China,we studied the carbon storage and its characteristics of dynamic change.The result showed that:(1)The total carbon storage of Eucalyptus urophylla×E.grandis plantation ecosystem in the order of 3a(195.25 t·hm^-2)>5a(169.57 t·hm^-2)>8a(166.70 t·hm^-2)>2a(165.00 t·hm^-2)>1a(111.84 t·hm^-2),respectively;Carbon storage of different ages in different layers appeared:soil layer>vegetable layer>litter layer,underground>aboveground;Carbon storage of vegetable layer is 4.87-80.54 t·hm^-2,contributed 4.36%-48.31% to the total carbon storage of the ecosystems,and grew with ages;The carbon storage of litter layer is 0.92-3.25 t·hm^-2,only contributed 0.82%-1.91% to the total carbon storage,appears descend trend with ages;The order of carbon storage of soil layer is 3a(162.53 t·hm^-2,83.24%)>2a(141.55 t·hm^-2,85.79%)>5a(112.26 t·hm^-2,60.22%)>1a(106.05 t·hm^-2,94.82%)>8a(84.50 t·hm^-2,50.69%).(2)Tree layer stored the highest carbon storage(3.10-78.96 t·hm^-2)and comprised 63.64%-99.25% of carbon storage in vegetable layer.The carbon storage of tree layer in different organs was positively different,stem stored the highest carbon storage(1.58~68.84 t·hm^-2),and accounted to 50.90%-87.18%,which also increased with ages,the other organs distributing sequence of the carbon storage in tree layer is branch(4.97%-12.17%),leaf(1.97%-22.36%),root(5.87%- 14.57%),all decreased with ages.(3)The average annual net carbon fixation of Eucalyptus urophylla×E.grandis plantation is 11.73 t·hm^-2·a^-1,where 2a(16.03 t·hm^-2·a^-1) forest stored the highest,respectively,3a forest is a better species of carbon sequestration forestry with high capability of carbon deposition,8a annual net carbon fixation up to 11.96 t·hm^-2·a^-1,and flat with 5a.Therefore,to improve the eucalyptus forest ecological service function and reduce its negative effect will be conducive to the development and growth of eucalyptus plants.