By arraying tobacco rooted plantlets with the different wave length and ratio of light emitting diodes(LEDs),with fluorescent lamp(CK) light as control,the effects of light quality on physiological characteristics and growth were investigated.The results showed that:(1)Red-blue-green(RBG) and Red-blue-white(RBW) light enhanced the heights,leaf lengths and leaf widths,leaf area,shoot diameter,root length,number of root and dry weigh of plant,and the contents of chlorophyll were also up-graduated,but those of treatments were no significantly differences.(2)RBW light treatments led to higher content of soluble sugar and C/N ratio,RBG light treatments led to higher content of free amino acid,and significantly higher than that of other treatments;for all light treatments,tobacco leaf soluble protein content is significantly higher than that of CK light treatment,1Red-blue(1RB) light treatment led to higher content of soluble starch,and significantly higher than that of CK light treatment.(3)Fluorescent lamp(CK) light treatments led to higher contents of MDA,and significantly higher than that of other treatments;while decreased activities of SOD,CAT and POD in the leave,and significantly lower than those of other treatments;which red light lowered content of MDA and enhanced activity of POD,and CAT activity is the highest.LED light source can significantly reduce the MDA content of tobacco plantlets,reduce the membrane lipid peroxidation damage,promote the growth of tobacco plantlets,and the main reason lies in its regulation metabolism of the activities of antioxidant enzymes in response to photo-oxidative stress.