The invention relates to the technical field of plant cultivation by artificial light, particularly provides a light environment method for full-artificial light cultivation of plants in order to provide a full-artificial light source for plant growth. The light source herein includes light wave 620-760 nm in frequency; the light wave 620-760 nm in frequency accounts for 64-76% of the whole photonquantity of the light source. Compared with traditional light sources, such as existing fluorescent lamps and high-voltage sodium lamps, the light source proportion and the light source combination mode employed herein help greatly increase the yield of plants. Compared with traditional LED light proportion schemes, the light source proportion herein has the advantages that the selected light frequency is more accurate, influence from other plant growth parameters is little, better specificity is imparted to the promotion of plant growth process, and the precise light wave frequency, peak wavelength and photon ratio precise combination and proportioning allow the plant growth effect to be controlled more precisely, so that plant growth is promoted.