Abstract: In order to maintain best cigarette quality and eliminate the influences of mildewed and off-grade tobacco strips, the strip cases containing mildewed strips were carefully examined, it was found that the moisture content and density of the strips in the cases were higher than the set values. Therefore, a monitor device was adopted, once moisture content or density higher than the set values was found, the case would be removed off the processing line. After the application of that technology, the frequency of strip case containing mildewed strips found in primary processing line reduced from 83 to 8 cases per year. Further, the influence of the proportion of off-grade strips in cases on cigarettes'sensory quality was analyzed, and a laser sorter was used to reject the off-grade strips, the sensory evaluation score of cigarette raised by 3.5 points because of that improvement.