Abstract: Red light, blue light, red + blue (R+B) light generated by light-emitting diode were applied during tomato color-changed period, and white light generated by fluorescent lamps was used as control. The effects of different light qualities on fruit quality of tomato were studied. The results showed that the lycopene content was the highest and the vitamin C(Vc) content was the lowest under red light among the treatments. The contents of Vc and soluble protein were significantly increased under blue light. There was no obvious difference in Vc content under R+B light treatment and the control, but R+B light had the superiority in promoting the content of soluble protein. The red light and R+B light were the most effective for the increase of the contents of the soluble sugar and titratable acid. Sugar acid ratio under all treatments were significantly higher than that under the control，and it was the greatest under R+B light treatment. The conclusion is that the major light qualities influencing tomato fruit quality during color-changed period are red light and blue light.