Abstract: The cultivable microorganisms were isolated from the leaf surface of flue-cured tobacco cv.K326 sampled at different aging stages,and the systematic status of these microorganisms and their phylogenetic relationship were analyzed with molecular biological method.The results showed that the amount and races of cultivable microorganisms on leaf surface obviously decreased with the prolongation of aging time.The major bacteria are Bacillus sp.and Enterobacter sp.;and Bacillus sp.is the dominant.Moreover,there is certain relativity between the amount of bacteria and the stalk position of tobacco leaf,namely,the amount of bacteria on middle leaf is larger than that on lower leaf,and that on upper leaf is the smallest.However,there is no obvious relativity between the amount and race of fungi and the length of aging time or stalk position of tobacco leaf.