The present invention relates to a method for reducing carbon dioxide from soil using biochar derived from corn residue and, more specifically, to a method for reducing carbon dioxide (CO2) from soil by adding biochar to soil which is derived from corn residue which is obtained by thermally decomposing the corn residue at 300-700°C for 1-5 hours. The present invention adds biochar to soil derived from the corn residue which is manufactured by thermally decomposing the corn residue at 300-700°C for 1-5 hours and reduces carbon dioxide generated from soils to atmosphere in order to reduce generation of carbon dioxide which is greenhouse gas and to contribute to prevention of global warming. Also, the biochar derived from the corn residue effectively works on soil quality improvement and contributes to increase of agricultural productivity by not only reducing carbon dioxide but stabilizing soil as a soil organic matter so that the present invention can be industrially used. [Reference numerals] (AA) Untreated