Spots on the arm may be hyperpigmentation spots, sun spots, freckle-like nevus and so on. 1. Hyperpigmentation spot: it can be irradiated locally by laser, and selectively act on pigment particles through the photothermal effect of laser to promote the fading and absorption of pigment spots. If the pigmentation spot is protruding from the skin, the pigmentation spot can be quickly frozen by low temperature liquid nitrogen, and the local tissues may fall off by themselves. 2. Sun spots: long-term in the external environment, irradiated by sunlight, may cause inflammatory erythema. Vitamin E cream and hydroquinone cream can be used to apply externally for depigmentation treatment. 3. Freckle-like nevus: the cause and mechanism of freckle-like nevus have not been fully clarified, which may lead to the appearance of black spots with the size of rice grains to peas on the skin or mucous membranes. Skin depigmenting agents such as hydroquinone cream can be given. It can also be removed by photoelectric type of treatment such as high-frequency electric knife and carbon dioxide laser. Spots on the arm are related to a variety of factors, and the best treatment plan for different spots is different, so it is recommended to go to the dermatology department of regular hospitals for a clear diagnosis and active treatment.