Abstract: In order to reduce the contents of starch and protein in tobacco and to improve its smoking quality, different types of tobacco leaves, such as flue-cured tobacco and burley tobacco leaves, were treated with various enzymes. The flue-cured tobacco leaves (B3F and B4F)were treated with amylase, saccharogenic amylase, and proteinase, respectively or simultaneously. The burley tobacco leaves were first treated with the proteinase, then cased and roasted. The results showed that 1)the reduction of protein and the increase of water soluble sugars in fluecured tobacco treated simultaneously with the amylase or saccharogenic amylase and proteinase were comparable with those of the same tobacco treated with these enzymes under their optimal conditions respectively, and 2)the smoking quality of the burley tobacco leaves treated was much better than that of the control.