Abstract: The fluidized bed cut stem dryer is a system of large thermal inertia,the control system which controls the moisture content of dried cut stem by regulating the temperature in the 3 drying sections of the dryer has the disadvantages of slow response and large fluctuation to disturbance.Therefore,a double loop moisture content control system based on air volume regulation and aided by temperature regulation was designed,whereby,air volume was regulated when moisture content fluctuated within a limited range,while air temperature was regulated when moisture content fluctuated beyond that limited range.After improving,the over-dried tobacco during start-up and run-down was reduced,the resistance to disturbance,response speed and stability of control system were improved effectively,and the average rate of cut stem up to the standard of moisture content increased from 83.88% to 95.56%.