The invention discloses a method for maintaining porous concrete through 
carbon dioxide. The method includes the following steps: (1) concrete is mixed and formed; (2) an obtained initial concrete body is placed into a pre-maintenance device for pre-maintenance, wherein the pre-maintenance temperature ranges from 15 DEG C to 25 DEG C, and the 
relative humidity ranges from 50% to 70%; air circulates through an 
air blower or a fan, wherein the pre-maintenance time ranges from 1 h to 18 h; (3) when the residual water-
cement ratio of the mixed material body obtained after pre-maintenance reaches a preset residual water-
cement ratio, the mixed material body is placed into a CO2 maintenance container, vacuumizing is carried out, then CO2 gas is led into the CO2 maintenance container for CO2 maintenance, the gas is discharged after maintenance is completed, and maintenance is stopped. By means of the method, control over the 
moisture content of the concrete body can be achieved, the 
carbon dioxide gas 
absorption capacity of the concrete can be effectively improved, and the quality of a concrete product can be effectively improved; in addition, the waste 
greenhouse effect gas, namely the 
carbon dioxide gas can be effectively used, the emission of the 
greenhouse gas can be reduced, the environment can be protected, and the 
greenhouse effect can be suppressed.