Abstract: In order to reduce temperature fluctuation of the processing gas or minimize the amount of over-dried tobacco at the head tobacco drying stage, the temperature control system for the combustion furnace in a CTD-1 pneumatic cut tobacco dryer at the head tobacco drying stage was modified. By adding a PID controller and a valve opening position monitor, the original single closed-loop control circuit of the control system was replaced by a double closed-loop cascade control circuit to real-timely monitor and accurately control the opening status of the fuel/air proportioning valve at the head tobacco drying stage. Ideally, the opening position of the fuel valve is linearly positively correlated to the fan motor frequency. Therefore, the opening position of the fuel valve and fan motor frequency can be automatically synchronized by a servo motor. To ensure combustion efficiency, the initial opening of the fuel/air proportioning valve at ignition time is set at 12%, and the highest fuel valve position during steady stage of tobacco drying is set at 60%. The modified control system was tested on the cut tobacco for cigarette brand "Septwolves (Chunjing, Xiamen)" in Xiamen Tobacco Industrial Corporation Limited. The results showed that at the head tobacco drying stage, the time for the furnace to approach to its stable temperature was reduced by 41 s/batch, the extreme temperature difference of the processing gas was reduced by 3.4 ℃, the amount of over-dried tobacco was reduced by 3.0 kg/batch, the QI score for the moisture content in the output tobacco was increased by 5 points, and the fuel consumption was reduced by 7 kg/batch. This technology provides support for promoting the consistency of cigarette quality.