Abstract: In order to reveal the mechanisms of alleviating stress-induced damage and application techniques of fulvic acid potassium in tobacco, effects of fulvic acid potassium on growth of flue-cured tobacco seedlings under drought stress were investigated by hydroponic experiments through physiological and molecular biological methods. The results showed that under drought stress, the water contents and water potential in leaves of flue-cured tobacco seedlings were significantly decreased, and the accumulation of proline and soluble sugar were significantly increased. Compared with drought stress alone, foliar spraying fulvic acid potassium could effectively improve the contents of soluble sugar, soluble protein, and proline to maintain high osmotic potential in cells, alleviate the decline of water contents and water potential in leaves, therefore enhance water-absorbing ability of flue-cured tobacco seedlings, and improve its drought resistance. In conclusion, fulvic acid potassium could alleviate stress-induced damage to flue-cured tobacco seedlings and improve its drought tolerance through increasing accumulation of osmolytes.