Photodynamic therapy is a method of physical therapy belonging to the skin diseases, through the photosensitizer in the lesion tissue focused on a specific wavelength of light or laser irradiation is excited, the production of singlet oxygen or other free radicals, thus causing necrosis of the lesion tissue, the normal tissue damage is small. The commonly used clinical photosensitizers are 5-amino ketoglutaric acid and Hempofen; the commonly used light sources are helium-neon laser, argon ion dye laser, discontinuous laser and pulsed laser. Indications include solar keratosis, basal cell carcinoma, early superficial squamous cell carcinoma, viral warts, Bowen’s disease, bright red nevus and so on. Adverse reactions include localized burning sensation, pain, and erythema. There are skin diseases need to first go to the hospital for examination, under the guidance of the doctor to choose the appropriate treatment measures.