Abstract: Three different varieties of tobacco dry seeds were irradiated with various doses of (200~400Gy) 60Coγ-ray, the seed germination and the character of seedling stage of M1 were surveyed. The data obtained was treated with the method of multi-comparison of new-multiple significant ranges. The germination rate, vigor of germination, germination index and the length of young roots and buds after 7 and 14 days of M1 during different bearing periods were researched. The results indicated that at the range of 200~400Gy, with the increasing amount of the dose, germination rate, vigor of germination and germination index decreased, young roots and buds grew slowly. The difference between each dose and control reached the level of 0.05 or 0.01 significance. To the length of young roots and buds, different doses of γ-ray had great effect on the length of young roots and buds most, the young roots and buds were restrained strongly (the difference between each dose and control reached 0.01 level significance), had less effect on germination index, vigor of germination and germination rate.