Abstract: To study the effects of light intensity on germination of light sensitive and insensitive tobacco seed, seeds of 19 cultivars were germinated under light and dark conditions. The results showed that seed germination varied with tobacco cultivars under dark condition. According to the cluster analysis, 19 tobacco cultivars were clustered into three groups: light sensitive cultivar, intermediate light sensitive cultivar and light insensitive cultivar. NC297 and MS Yunyan 87 were used as the light sensitive cultivar and the light insensitive cultivar to study the effects of light intensity on tobacco seed germination. The results showed that the seed germination energy, germination percentage and germination index of the two cultivars increased with the enhancement of light intensity, and reduced gradually when the light intensity was more than 3730 lx. The reverse case was found in germination time. It can be concluded that the best light intensity for light sensitive and insensitive tobacco seed germination is 3730 lx.