Abstract: In order to investigate the effects of glycine betaine and proline application on the resistance to drought,a pot culture experiment was carried out to study the effects of glycine betaine and proline spraying on the antioxidant metabolism of flue-cured tobacco under drought stress. The results showed that:1)Under drought stress, the contents of chlorophyll and soluble protein were increased,while MDA content was decreased to different extents by spraying glycine betaine or praline, which effectively delayed the consenescence of the plants. 2) Glycine betaine and proline spraying improved SOD activities to different extents and promoted proline accumulation in tobacco leaves,which were the important factors improving the drought resistance of flue-cured tobacco. 3) Either glycine betaine or proline could be used as exogenous regulating substance for flue-cured tobacco under drought stress. Glycine betaine was superior to proline in decreasing membrane lipid peroxidation in tobacco leaves,however,from the point of increasing CAT activity and decreasing MDA content,it would be more effective to apply the two together.