Incandescent lamps, fluorescent lamps, metal halide lamps, high pressure sodium lamps, and emerging LED lamps have all been used in greenhouse light supplementation. Among these types of light sources, high-pressure sodium lamps have higher light efficiency, longer service life, higher overall energy efficiency, and occupy a certain market position, but high-pressure sodium lamps have poor illumination and low safety (including mercury). Problems such as inaccessible proximity are also prominent. Some scholars have a positive attitude toward LED lights in the future or can overcome the problem of insufficient performance of high-pressure sodium lamps. However, LED is expensive, the fill light technology is difficult to match, the fill light theory is not perfect, and the LED plant fill light product specifications are confusing, which makes users question the LED application in plant fill light.