Abstract: The cut tobacco expanding system composed of a conditioner and a dryer has the disadvantages of its complicated structure and control system,and high energy consumption;the expanded tobacco tends to be overdried and presents different physical-chemical properties,which affects the sensory quality of cigarette. Therefore,a pressurized device for pre-expanding cut tobacco was designed,which was mainly composed of a hood for feeding,pressurized airlock and steam supplying system. Steam was sprayed into the body of airlock to create a pressurized condition within the airlock,to complete the tobacco expansion process along with humidifying in a short time. The results of application showed that:the designed device could be an alternative to the traditional conditioner or to the airlock feeding device in a pneumatic drying system,which simplified the process of cut tobacco drying and expanding,occupied less site area and consumed less energy. The over-drying of cut tobacco was avoided,the duration of heating and humidifying decreased from 1 minute to 2-3 seconds, the expansion effect and intrinsic quality of cut tobacco were also improved.