Abstract: In order to promote the uniformity of water addition and reduce the fluctuation of moisture content in cut stems, the humidifying circuit and control mode in super conditioner for cut stems were modified. A membrane valve was added in steam compensation circuit to realize precise and automatic control, and the steam compensation circuit was serially connected to water addition circuit. In the case that the compensation steam contained excessive condensate or the moisture content in cut stems was higher, only steam compensation circuit worked; at the time the steam compensation circuit failed to complete cut stem conditioning, the water addition circuit started to work together. The results showed that after improvement, the moisture content in cut stems out of super conditioner was 35.94%, which satisfied the requirement of production; standard deviation decreased by 0.14 percentage points, process capability index Cpk increased by 0.59, and sigma level raised by 1.54. The stability of the system is promoted and the moisture content in cut stems is controlled accurately.