Effects of different light qualities (blue light, green light, yellow light, red light and white light) on the growth and physiological characteristics of tomato seedlingswere studied. The results showed that under red light the drymatter accumulation, leaf area, chlorophyll content, photosynthetic rate, soluble sugar
content and total sugar contentwere allmaximalwhile the chlorophyll a /b ratio and total nitrogen content were lowest compared with the other treatments. The stem diameter, leaf area, root activity and photosynthetic rate of tomato seedlingswith blue lightwere higher than that ofwhite light. The healthy index of the seedling treated by blue lightwasmaximal, and the red light treatment was the second. It is concluded that blue light or red light treatment could accelerate the growth of tomato seedlings, and benefit the breeding of healthy seedling. The blooming was early and the yield was imp roved obviously by blue light treatment.