Carbon and nitrogen storage in different plantation ecosystems of Erythrophleum fordii, Castanopsis hystrix and Pinus massoniana in subtropical south China were studied. The results showed that the allocation of C in the organs of the different tree species had no significant correlation with their age, while that of N had closer relationship with the age. The N concentration in young organs was higher than that in aged ones and the C/N ratio was higher in aged organs than that in young ones. The N concentration was higher in all components of the nitrogen-fixing species (E. fordii plantation) than that in other species (C. hystrix and P. massoniana plantations). There was an obvious enrichment of C and N in the topsoil of the plantation ecosystems. The total ecosystem carbon storage of E. fordii, C. hystrix and P. massoniana plantations was 236.22 t/hm², 267.84 t/hm² and 200.57 t/hm² and nitrogen storage was 17.91 t/hm², 12.38 t/hm² and 10.59 t/hm², respectively. Carbon storage of tree layer occupied 42.57%, 36.31% and 40.28% while 0-100 cm soil occupied 55.77%, 62.52% and 57.83%, respectively. Nitrogen storage of soil occupied 92.00%, 93.72% and 95.53%. Our study indicated that most ecosystem carbon and nitrogen storage of the plantations stored in soil. Carbon sequestration ability of C. hystrix plantation is higher compared to other two plantations.