Pigmentation is a pigmentation disorder, and common pigmentation includes freckles, melasma, age spots, coffee spots, Mongolian spots and so on. Freckles are autosomal dominant disorders, which occur mostly after the age of 5 and increase with age. They are commonly found on the exposed parts of the face, neck and shoulders, upper back and back of hands, and are light brown to dark brown spots from the size of a pinpoint to a green bean. Melasma is a pigmented disease of unknown etiology, suspected to be related to female hormones or various chronic diseases, medications, cosmetics and sun exposure, and is a symmetrical and limited light brown to dark brown patch on the face. Age spots, also known as senile warts and seborrheic keratosis, are mostly seen in men around 50 years old after middle age, and the lesions often increase with age. The lesions are usually found in the areas with strong sebaceous secretion, such as the face, neck and back, but also in the limbs and arms, and the early damage is yellowish or yellowish-brown flat patches, and then gradually increase in surface roughness, covered with greasy scabs. Coffee spots, also known as coffee milk spots, are light brown patches that can be found at birth, ranging from light brown to dark brown in color, but the color of each patch is the same and very uniform, the shade is not affected by sunlight, the size varies from a few millimeters to tens of centimeters, the border is clear, and the texture of the surface skin is completely normal. It is mostly seen on the trunk and will not fade away on its own. Mongolian spot is a benign blue patchy damage on the lumbosacral area, which is usually present after birth, deepens within a period of time after birth, and then fades with age, often fading on its own at the age of 5-7 years without leaving any trace, and does not need treatment. The traditional treatment measures for various pigmentation include: cosmetics, acupuncture, liquid nitrogen freezing, chemical corrosion, grinding, high frequency electric knife, oral medication and topical medication. Various pigmentation spots need different laser treatments. Freckles can be treated with C3 laser, Q-switched Nd:YAG laser and photon. For laser treatment, basically one treatment is enough; for photon treatment, several treatments are needed to basically get rid of them, with an interval of 20 days each time. Melasma can be treated with C6 laser or photon, but it needs to be treated with medicine, otherwise it can only reduce the symptoms, but cannot guarantee the complete elimination. Age spots can be treated with CO2 laser or Q-switched Nd:YAG laser or C3 laser, which have stronger effect and basically only need one treatment. Coffee spots can be treated with Q-switched Nd:YAG laser, C3 laser or 532 laser, which are more effective but require multiple treatments with an interval of about 3 months each time. Mongolian spots do not require treatment.