Abstract:In 2007—2008, taking Jiyan 9 which widely planted in Yanbian as testing material, dynastic variations of chemical components, physical characters and aroma quality of flue-cured tobacco were studied. The result indicated that: the chemical components of 65 days of tobacco leaves were more harmonious; The physical characters perform well; The total aroma constituents the other aroma constituents and neophytadiene were high; The browning reaction products and carotenoids contents improved; The smoking scores were the highest, the aroma quality and quantity were the best. In conclusion, tobacco leaves were harvested at 65d with the best cured leaf quaulity.