Abstract:The upper leaves of flue-cured tobacco of tobacco cultivars Zhongyan 100 and Yunyan 87 were used to study the effect of different drying periods (48, 60, 72 h) on the activities of amylase and starch phosphorylase. Compared to the routine baking process, amylase activity of the leaves pretreated with air drying reached its first peak 12 h earlier during the baking process, which extended the life time of amylase; the starch phosphorylase activity in the early period of baking process decreased, but in the late period the decrease was not obvious. The leaves pretreated with 60 h of air drying had high activities of amylase and starch phosphorylase, high amylase degradation, and the amylase content was low while the contents of water-soluble total sugar and reducing sugar were high in these leaves, these cured upper leaves with balanced chemical components are considered highly applicable.