Abstract: The germination vigor, germination rate and related enzyme activities of K326 tobacco seeds socked with chitooligosaccharide solution of different concentrations were tested, respectively, to explore the effects of chitooligosaccharide on the germination and related enzyme activities of tobacco seeds. The results indicated that within the concentration range from 0.2 mg/mL to 1.0 mg/mL, chitooligosaccharide could improve significantly germination vigor and germination rate of tobacco seeds, and that the optimum concentration for treatment was 0.4mg/mL. The germination vigor and rate of seeds treated by the optimum concentration were 40% and 6% higher than those of the control, respectively. The peroxidase (POD) activities in the germination seeds treated by 0.4mg/mL chitooligosaccharide were significantly higher than that of the contrast (seed socking with water). And the activities of superoxide dismutase (SOD) and phenylalanine ammonialyase (PAL) in the germination seeds treated by 0.4mg/mL chitooligosaccharide were also significantly higher than those of the control of not-seed- socking. The possible mechanism in improving germination vigor, germination rate of chitooligosaccharide was discussed based on the results mentioned above.