Photodynamic therapy (PDT), a new disease treatment based on the interaction of light, photosensitizers and oxygen, is a kind of photosensitization reaction with the participation of oxygen molecules and accompanying biological effects. In recent years, it has been more widely used in the field of dermatology and venereal disease treatment, and has achieved remarkable results. In the 1950s, people began to use photodynamic methods for the early diagnosis of tumors, and photodynamic therapy began to enter the clinical practical stage, and achieved good results in the treatment of solar keratosis, superficial basal cell carcinoma, bright nevus and Bowen’s disease, and it is safe and well-tolerated. In 1995, the first PDT system was created in the United States, which consisted of photofrin, laser and fiber optic delivery system for the treatment of severe dysphagia due to esophageal cancer. on December 7, 1999, the FDA approved the marketing of 20% aminolevulinic acid hydrochloride (ALA) solution for the treatment of head and face The photodynamic therapy of actinic keratoses. In recent years, photodynamic therapy has been applied to vulvar lesions, especially condyloma acuminatum, with remarkable results. Condyloma acuminatum (CA), a benign epidermal proliferative disease caused by HPV infection, is the most common sexually transmitted disease with types 6, 11, 16, 18, 31, and 33 infections. In female condyloma acuminata, HPV infection is closely associated with the development of tumors. The exogenous ALA can selectively distribute and accumulate in the acromegaly cells and transform into protoporphyrin IX (a photosensitive substance that exists in the normal metabolism of the body), which can effectively kill the target cells using specific wavelength, energy and suitable time window irradiation. It is also possible to clear the infection especially in subclinical state, thus reducing the recurrence rate. More ALA penetrates into the condyloma acuminatum tissue compared to the surrounding normal skin tissue. Photodynamic therapy is able to selectively kill tumor cells and abnormally proliferated cells after viral infection, with no damage to normal cells. It also has no contraindication for sensitive and refractory areas that are difficult to perform by conventional methods such as surgery, laser and freezing. Several clinical observations in urethral opening suggest that the total recurrence rate after photodynamic continuous treatment is only 5%, and the local anatomical structure is well preserved after treatment without scar formation, etc. ALA-PDT is simple, easy to operate, repeatable, with high target tissue selectivity, low toxic side effects and high safety through local administration. The treatment has a good cosmetic effect and does not leave scars. After local administration of ALA, not only the clinical lesions and subclinical infections can be fully displayed, but also the latent infection sites can be shown under specific wavelength light excitation, which has the significance of localization and diagnosis.