Abstract: The paper aims to decrease the starch content and improve the quality of flue-cured tobacco leaves. B5221 and YTK1 isolated from middle tobacco leaves of‘Yueyan 97’were mixed into microbial preparation with concentration of 2.5%, 5.0%, 7.5%, 10%, which was sprayed on the upper leaves before curing, to study the effects on starch degradation and quality of flue- cured tobacco leaves. The results showed that the chemical composition of the tobacco leaves were changed by B5221 and YTK1 agents, the contents of soluble sugar and the ratio of total sugar to nicotine and total nitrogen to nicotine were increased, but the contents of starch and protein were decreased. At the concentration of 2.5%, microbial preparation had better effect, the starch and protein degradation were more, the sugar content increased the least, the contents of nitrogen and nicotine increased, and the sense organ quality was improved. Therefore, 2.5% microbial preparation of B5221 and YTK1 was suitable for improving the quality of flue-cured tobacco leaves.