Abstract: The effects of C0² enrichment on the allocation of biomass，C and N accumulation in rice organs under 2 levels of N were studied．The results shown that the elevated C0² decreased significantly the allocation of biomass and C content in rice leaves and increased their allocation in shoot，ear and root，decreased the allocation of N content in leaves and increased the allocation in ear．Under 1owar N and normal N trea tments。the alloc ation of N in ro t decreased by 9.67％ and 13.1％ respectively at heading stage and increased by 3.5％～ 26.6％ at other stages ．the allocation of N in shoot increased by 7.03％ and 5.71％ atjointing stage and decreased by10.5％ and 7.43％ at ripening stage respectively．There was not significant influence of N levels on the allocation of biomass，C and N in rice organs．