Abstract: In order to minimized the fluctuation of output moisture content in tobacco, the control system in HAUNI's ordering cylinder was modified as follows:1) a closed loop control system was designed for the output end of the cylinder, to feed the value of output moisture content back to PID regulator and adjust the amount of water added at the rear end timely corresponding to the change of moisture content; 2) a moisture meter was installed at the input end of the cylinder to monitor the fluctuation of moisture content in input tobacco; 3) ramp control principle was introduced to optimize the control of water addition during the start and finish of operation. The results showed that:after improvement, the control curve of output moisture content became stabler obviously; the ratio of cut tobacco with qualified moisture content increased from 88.02% to 98.96%; while the amount of over-wet cut tobacco during start and over-dried tobacco during finish of operation decreased from 260 to 82 kg; the standard deviation decreased from 0.91 to 0.36; the process capability index (Cpk) increased from 0.45 to 1.35.