Abstract: To improve and perfect seedling technology for transplanting mode of small tobacco seedlings, based on physical parameters of seedling holes, effect of seedling tray specification on growth of seedlings was analyzed to optimize parameters of seedling tray． Results showed that, compared with CK, upper surface area of seedling hole decreased by 18.70%～54.41%, seedling tray's hole density increased 21.21%～102.02%． Change of seedling hole specification had significant effect on agronomic characteristics after covering tray, volume of seedling hole decreased by more than 56.92%, fresh weight and dry weight of roots decreased significantly, root activity decreased significantly by 10.17% compared with CK, content of MDA in leaves was significantly increased, 146.44% higher than CK, stress resistance decreased． Based on CK, it was feasible to reduce volume of seedling hole（range less than 56.92%）and increase density of seedling hole（range less than 77.78%）． Combined with seedling cost, upper aperture 2.41～2.54 cm × 2.18～ 2.35 cm, lower aperture 1.5 cm×1.5cm, hole depth 4 cm, seedling tray's hole density 315 ～ 352 holes, seedling tray's length and width 60 cm × 40 cm, which could be suggested to be popularized and applied in tobacco-growing area．