Abstract: Light is a basic environmental factor in plant growth and development, which plays an important role in the regulation of plant growth and metabolism. In this study, the effect of red, blue, different ratios of red and blue (1∶1, 1∶2, and 2∶1), and white (control group) LED light on the growth and main secondary metabolites of tissue culture seedlings in Vaccinium dualianum was investigated by measuring the physiological parameters and the content of 6'−O−caffeoylarbutin (CA). The results showed that the growth of seedling height was promoted under the treatment of monochromatic red light, and MDA content and POD activity of seedling were enhanced under the treatment of monochromatic blue light. The chlorophyll content and resistance to light stress of seedling were increased under the treatment of combination of red and blue light. Of these, the tissue culture seedlings had a higher SOD activity when the ratio of red and blue light was 1∶1. The soluble sugar and soluble protein contents of tissue culture seedlings increased first and then decreased with the increase of red light proportion, while the MDA content and POD activity enhanced with the proportion of blue light increased. The highest content of CA in tissue culture seedlings was (21.02 ± 0.56) mg/g when the ratio of red to blue was 1∶2 with 1.5 fold higher compared to the control group, while its content decreased under other light-quality treatments. The results could provide an experimental basis and reference for the regulation mechanism of CA production in V. dunalianum.