Abstract: In order to solve disorder by cultivating tobacco seeding with the shed nursery in low temperature and weak light of winter in Hunan, it was studied for effect on light intensity to growth and main physiological index of the tobacco seeding. Tests were separately carried out with the light emitting diodes in proportion of blue: red =1:1 (supply light intensity was respectively 3000, 4500 and 6000 lx) to supply light of tobacco seeding by combination light in water temperature constant conditions. Results showed that growing leaves day of tobacco seeding decreased and blade growth rate of tobacco seeding accelerated, with the increase of light intensity. The treatment existed significant different. Supplying light intensity reached 6000 lx, stem circumference of tobacco was stout and height, and dry fresh weight and dry fresh ratio was high, and seeding dry matter was accumulated most. Plastid pigment and root activity were affected by light intensity, including chlorophyll a, chlorophyll b, carotenoids and root activity increased with light intensity enhancement, but the chlorophyll a/b ratio decreased. It showed that supplying light was helpful to cultivate tobacco seedling and to improve tobacco seedling quality.