The invention relates to a cut tobacco quality control method and system based on airflow drying. The method comprises the steps that outlet water is selected as a factor influencing airflow drying quality, the difference between an outlet water actual value and an outlet water target value is counted, and the change area of the outlet water difference value is determined; the change area of the difference between the outlet water actual value and the outlet water target value is divided into N sections; the current outlet water is collected, the difference between the currently collected outlet water and the target value is subjected to section judgment, and the opening degree of a mixing air door is adjusted according to section changes. According to the method, the opening degree of the mixed air door is adjusted according to the deviation degree of the outlet water actual value and the outlet water target value in a partition mode, the outlet water in the airflow drying procedure can be precisely controlled, the outlet water in the production process is kept fluctuate around the target value as much as possible, the fluctuation range of the outlet water is reduced, and the quality of the cut tobacco outlet water is improved.