The invention discloses an air flow regulation structure, a fresh air machine and an air-conditioning method. The air flow regulation structure comprises a face cover, a driving mechanism, an air quality sensor and a controller, wherein the face cover is used for covering the air outlet end of a fresh air machine shell; the power output end of the driving mechanism is connected with the face cover, and the driving mechanism is used for driving the face cover to move in the direction far away from or close to the air outlet end of the fresh air machine shell; the air quality sensor is used fordetecting the quality grade of indoor air; the controller is in communication connection with the driving mechanism and the air quality sensor. The air flow regulation structure can continuously detect the quality grade of the indoor air, drive the air outlet end of the fresh air machine shell opposite to the face cover to move according to the quality grade of the indoor air and regulate the airflow of the fresh air machine to enable the quality of the indoor air to be within the preset grade all the time, and usage experience is good.