UV therapy is an important method of treating skin diseases. Traditional UV therapy includes long-wave UV plus psoralen (PUVA), broad-spectrum medium-wave UVB (BBUVB). Ultraviolet therapy emits wavelengths in the range of 280-400 nm. Clinical studies have shown that light below 300 nm can cause skin burns and even increase the chances of skin cancer. Narrow-spectrum UVB allows patients to receive light in the wavelength range of 311-312 nm (this range is the most beneficial part of natural sunlight and is also the safest), and narrow-spectrum UVB treatment does not require the use of other complementary medical drugs, avoiding the side effects associated with the use of photosensitizing drugs in traditional PUVA methods. Narrow-spectrum UVB is mainly used for the treatment of psoriasis, vitiligo, chronic eczema, atopic dermatitis, herpes zoster, pityriasis rosea, severe seborrheic dermatitis, pemphigus, palmoplantar pustulosis, pemphigus vulgaris, paronychia, chronic skin ulcers, mycosis fungoides, and various photographic diseases.