The principle of IPL is usually the principle of photothermal effect, which mainly uses intense pulsed light to produce wavelength, the range of emission spectrum is 400-1200 nm, and then penetrates directly into the deep skin, the depth of treatment is up to 4 mm below the skin, the shorter wavelength of the output wave band is used to treat vascular and pigmented lesions, while the longer wave band can achieve the effect of skin rejuvenation.