There are many surgical methods for anal fistula, but the basic treatment principles are the same, and the key is to: 1) find and treat the internal opening correctly; 2) drain the wound well; 3) preserve the rectal ring as much as possible. These three points are easy to say, but it is not simple to really implement them well. First of all, it is sometimes difficult to make a correct judgment of the endografts of complex (or extra high) anal fistulas because there are many gaps around the anorectum, and some of them are caused by the closure (or temporary closure) of the primary endografts before the infection spreads to form complex (or extra high) anal fistulas, and some of them have multiple endografts at the same time. The fistulae are deep and large due to the closure of the orifice, the bifurcation of the fistulae and the depth of the lumen. The two sides of the fistula are the contradiction between the traumatic drainage and the preservation of the rectal loop, and sometimes the choice is as difficult as not having both the fish and the bear’s paw. For patients with complex fistulas that cannot be determined by preoperative intraoperative examinations (including probing, injection of melanin, hydrogen peroxide, etc.), I generally do not perform preoperative imaging, magnetic resonance and ultrasound endoscopy because these examinations do not have much practical significance in determining the location of the internal opening and the course of the fistula in the small number of cases I have done, and I have always believed that ( I have always believed (and this is what the old revolutionaries in the army always taught) that a good doctor should not only be able to cure the disease but also spend as little money as possible. For complex anal fistulas, I think that the most primitive method of using a probe to cut and probe is still the most effective method. If the fistula can be found directly after probing from the outside, the role of the probe need not be questioned; if the fistula cannot be found directly after probing from the outside (or the lumen is too large and deep, or the fistula is curved), I will first cut the outside and properly widen the wound to scratch the rotten tissue and fully reveal the fistula before further investigation, and then further surgery depending on the actual situation. The following is a report of several clinical situations combined with specific cases: 1, low complexity anal fistula regardless of the number of internal mouths can be cut open all at once, the external fistula tracts between the ports are cut, open, floating line, incision suture, etc. depending on the specific situation. 2, the inner mouth in the tooth line and fistula penetration to the anal canal above the rectal ring of high anal fistula as far as possible to perform low incision high drainage. If the fistula is small, the external expansion cannot achieve the purpose of drainage, or if the patient’s anal canal is long and bleeding is more when the sphincter is opened, consider hanging a wire, and hang as little or as little as possible from the anorectal ring tissue. 3, not found in the internal mouth, fistula small and deep to the outside of the intestinal wall of the high anal fistula, external expansion of the invasive can not achieve the purpose of drainage, it is appropriate to low incision of the weakness of the intestinal wall through the high hanging line. 4, the anal fistula occurs in the perineum of the anterior wall of the anus more superficial, although the internal mouth is usually in the anal fossa corresponding to the external mouth, but due to the small gap in the anterior wall is often closed, you need to follow the vine to gradually cut and explore in order to find the internal mouth, surgery will be cut inside and outside the mouth and fistula, appropriate expansion to make drainage can be smooth. 5. In posterior horseshoe fistula, the internal opening is often in the posterior middle or slightly to the left and right of the anal fossa, and to ensure unobstructed drainage, it is often necessary to cut open the posterior wall of the anal canal. Through the above individualized and principle-based surgical operation, we can effectively reduce postoperative pain, simplify and shorten the treatment course, and most importantly, maximize the protection of anal function and avoid anal deformation, while improving the success rate of the operation.