The fistula surgery means that the fistula is completely cut open, and if necessary, the scar tissue around the fistula can be properly trimmed, which can ensure smooth drainage and gradual healing of the surgical wound. The first one is to hang a wire, which does not affect the function of the anus, the scar is small, and the drainage is smooth, mainly for low anal fistulas within 4cm from the anus, with internal and external openings, and also as an adjunct to open or excisional therapy for complex anal fistulas. The second, incision therapy, mainly for low simple anal fistula and low complex anal fistula, to high anal fistula incision, must be combined with hanging wire therapy, in order to avoid causing anal incontinence.