Acne vulgaris (acne vulgaris) is a chronic inflammatory skin disease associated with the sebaceous glands, with a prevalence of 70% to 87% and a significant negative impact on the emotional and social life of adolescents. The current treatment for acne includes topical medication, systemic medication and physical therapy. Photodynamic therapy (PDT) is a special physical therapy that uses exogenous substances accumulated in acne lesions as targets to regulate the pathophysiological process of acne. 5-ALA-PDT treatment for acne is based on the principle that when exogenous 5-aALA is administered, it is absorbed by ALA epithelial cells and follicular sebaceous glands and converted to endogenous photosensitizers through the heme synthesis pathway. It is converted to endogenous photosensitizer PpⅨ, which produces singlet oxygen and free radicals when irradiated with specific wavelengths of light, selectively kills Propionibacterium spp. PDT has the advantages of good tissue selectivity, superficial action, local treatment, few systemic side effects, and repeatable application without drug resistance, providing a new option for acne treatment.