Abstract: Flue-curing characteristics of flue-cured tobacco varieties Honghuadajinyuan, Zhongyan 100 and K326, which included changes of plastid pigments, water content and activities of polyphenol oxidase (PPO) were investigated, under the same curing conditions, in order to find out physiological and biochemical changes during curing process. The chemical compositions of cured leaves were measured and the appearances of economic characters were evaluated. The results showed that three tobacco varieties existed differences in yellowing process, water removal and activities of enzyme, Honghuadajinyuan performed slow loss of free water, high speed loss of bound water during fixing color stage, high ratio of free water and bound water, high activity of polyphenol oxidase, high chlorophyll content but low degradation, all these effected appearance quality after being cured; K326 performed rapid water loss during curing, low ratio of free water and bound water, polyphenol oxidase activity was at middle, the content of tobacco nicotine was high; the color change during the yellowing stage of Zhongyan100 was in accordance with water removal, with low PPO activity, low chlorophyll content, the percentage of fist-and middle tobacco leaves and average price were the highest.