An LED plant growth lamp and a light spectrum and application thereof, wherein the light spectrum contains: 500-599 nm light waves and 700-780 nm light waves, and the ratio of the number of photons in the 500-599 nm range and the number of photons in the 700-780 nm range is 0.9-1.6:1. The use of the present light spectrum may promote the indoor cultivation and growth of plants, and help to increase pharmaceutical composition yield per unit time and per unit area during industrial production.