Anal fistula is a common disease, called “hemorrhoid fistula” or “leaky sore” in Chinese medicine. The so-called anal fistula refers to the anal canal and rectum, is a common clinical condition, this disease can occur at any age, and is mostly seen in young adults. Patients with anal fistula are common anorectal diseases, accounting for about 1.67% to 3.6% of anorectal diseases in China. The main symptom is the repeated flow of pus or pus and blood from the perianal orifice and pain, which is called leakage, contamination of clothing and pants, and affects daily life and work. Surgery is currently the most effective method of treating anal fistula, and the conventional surgical method is the traditional low incision and high thread method. As early as the Ming Dynasty, Xu Chunfu recorded the treatment of hanging threads in the “Ancient and Modern Medical System”, citing the “Yong class ^ Inscriptions”. The traditional low-cutting and high-hanging procedure has its own unique advantages and has become the most effective and classic procedure for the treatment of anal fistula. However, it also has the disadvantage of taking too long to heal and being too painful. However, the traditional surgical approach has disadvantages such as long healing time and high pain for the patient. I use a variety of treatments for anal fistula by adding semi-closed sutures to the traditional low-cut, high-hanging procedure, which can reduce the healing time of the wound. Due to the semi-closed suture, the trauma surface is reduced, the contact surface for drug changes is alleviated, and by shortening the trauma healing time, the number of drug changes can be reduced, thus alleviating the patient’s pain. Anal site surgery is a type II surgical incision, which is susceptible to infection by various bacteria in anal stool if it is not drained properly. Whether infection occurs is related to various factors such as drainage of the trauma, type and number of bacteria, virulence, and immunity of the patient. The infection rate of the general fully closed suture incision is high, and once the infection has been caused it has to be opened again, causing secondary pain to the patient and even leading to the failure of the operation and the formation of a new anal fistula, causing recurrence. The treatment of anal fistula using semi-closed suture method, adequate hemostasis before suturing, such as wound bleeding accumulation below the suture part, easy to infection or even septic, leading to surgical failure. The suture requires starting from the base of the wound and gradually suturing the wound from inside to outside with 3-0 absorbable intestinal thread, leaving no dead space and reducing fecal contamination of the wound. In semi-closed sutured wounds, the iodophor solution enters the interior of the wounds due to the siphoning effect during the early (within 7 days) dressing change, which can kill the small amount of bacteria remaining inside, thus effectively preventing infection. In summary, the treatment of anal fistula by semi-closed suture is a modified procedure based on the traditional low-cutting and high-hanging procedure, which is a safe and effective procedure with shorter healing time, less pain, and no risk of increasing the chance of infection compared with the traditional procedure.