The invention discloses a method for shortening the tobacco leaf baking time of a closed barking room, belonging to the technical field of modulation of flue-cured tobacco. The method comprises the following steps: manually introducing oxygen in the front yellowing stage, so as to maintain the oxygen concentration in the closed barking room at 0.5%-2.0%; manually introducing carbon dioxide from the middle-later yellowing stage to a color fixation stage, so as to maintain the carbon dioxide concentration in the closed barking room at 0.5%-2.0%; and continuing to introduce carbon dioxide from alater color fixation stage to a tendon drying stage, so as to maintain the carbon dioxide concentration in the closed barking room at 0.1%-0.8%. The method has the beneficial effects that the respiratory action of tobacco leaves in the baking process can be adjusted, the baking time can be shortened, the quality of the tobacco leave can be improved, the utilization rate of the baking room can be increased, the energy consumption cost can be lowered, and the increase of farmer's income can be promoted.