Acne is a multifactorial chronic inflammatory skin disease of the hair follicles and sebaceous glands, which occurs in seborrheic areas. It is most common on the face of adolescents, especially moderate to severe acne, which affects the appearance and is prone to low self-esteem. The traditional treatment for inflammatory acne is usually topical application of benzoyl peroxide, fusidic acid, clindamycin and other ointments or oral tetracycline and other antibiotics, which can reduce the symptoms to a certain extent, but the course of treatment is long, with a lot of contraindications, and also prone to adverse reactions and drug resistance phenomenon. Photon treatment of inflammatory acne is currently more advanced a pure physical therapy technology, its efficacy is good, little pain, minimal side effects, mainly local stimulation of burning, can be resolved by cold compresses. Its indications are all inflammatory acne patients with non-photosensitized skin. The use of photon acne treatment instrument emits 420nm light, a high-energy specific spectral blue light, which can penetrate the skin and act on the porphyrin in the sebaceous glands. The porphyrin is stimulated to release monomorphic oxygen ions, which efficiently kills Propionibacterium acnes and eliminates inflammation; at the same time, it can inhibit the sebaceous glands from secreting sebum and reduce greasiness; it can also promote the recovery of acne inflammation, accelerate the fading of pigmentation and the repair of scars, and it has no side effects, which greatly reduces the chance of acne scarring after the treatment. Clinical observation found. The earlier the treatment, the faster the skin improves and the more obvious the effect. We found that acne treatment has a positive correlation trend with the number of treatments and results. For optimal results, a minimum of 5-6+ treatments are required, usually 1-2 treatments per week. In conclusion, the application of 420nm photon therapy for patients with moderate to severe acne is an effective treatment for inflammatory acne as there is no interference with normal life and study during the treatment period.