The invention relates to a carbon dioxide production method and especially relates to a method for reducing a carbon dioxide discharge amount in food-grade liquid carbon dioxide product production. The method comprises the following steps of 1, a denitrification process, 2, a first compression process, 3, a desulfuration process, 4, a dealkylation process, 5, a purification process, 6, a second compression process, 7, a liquefaction process, and 8, a distillation purification process. The method can greatly reduce a carbon dioxide discharge amount.