Abstract: The ways of enzymatic degradation of protein in tobacco was studied and the activities of various prloteinases under given conditions were compared. The results showed that the neutral proteinase was the most effective enzyme for reducing the Protein in tobacco among the proteinases used. Under the conditions of 120u/g, temperature 45℃, the moisture content 25%, and time of enzymatic degradation 4 hours, the neural proteinase could degrade about 12% protein in tobacco and thus the flavor of tobacco smoking was improved significantly.