In recent years, photodynamic therapy has become increasingly popular in the field of dermatology in China. Its principle is to artificially apply exogenous photosensitive substances to biological tissues, and when the tissue absorbing photosensitive substances are irradiated by the corresponding wavelength of light, they absorb photon energy and change from the ground state to the excited state, and its chemical degradation process can produce a large number of reactive oxygen species, which interact with a variety of biological macromolecules to produce cytotoxic effects and lead to cell damage The process of chemical degradation can produce a large amount of reactive oxygen species, which interact with a variety of biological macromolecules, resulting in cytotoxic effects leading to cell damage and even death, thus producing therapeutic effects. Photodynamic therapy is being widely used in common dermatological diseases such as warts, acne, and skin cancer. After 3 hours of dressing, photodynamic therapy was applied. The irradiation time is 20 minutes per spot, the spot diameter is about 2~3cm, to completely cover the dressing area is appropriate, the total energy of irradiation is generally 60-100mJ/cm2, and the treatment is once a week. The clinical cure rate can be more than 97%, and the recurrence rate is only 7-8%, the recurrence rate is much lower than the freezing, ionization, CO2 laser, foot leaf herb medicine and other conventional therapies, and the treatment is basically painless, no trauma, no scars, for the anal canal, vaginal cavity and other deep warts can also achieve the same effect.