Anal fistula surgery hanging dotted line is mostly applied to high anal fistula and complex anal fistula, clinical use of silk thread, because the silk thread is not elastic, so it will not cut off the anal sphincter. The main role of the dotted line in anal fistula surgery is to play the role of intracranial drainage. Complex anal fistula, high-risk anal fistula surgery, due to the deeper wound, in order to prevent surgical damage to the anal sphincter and lead to anal incontinence, can be hanging line treatment. The hanging of the virtual line more need to use silk thread, hanging placed between the sphincter, between the fistula, play the role of drainage, so that the internal secretion out, to prevent the formation of false healing. Rubber strips can also be used, but they cannot be tightened. After hanging the imaginary line will not appear to cut off the anal sphincter on its own, do not need to tighten, with the healing of the wound, you can hang the imaginary line 10-15 days after the removal of the time, the wound and then placed in gauze for drainage, until complete healing. The specific situation is recommended to go to the hospital, complete the auxiliary examination, clear condition, whether the need to hang the imaginary line treatment, need to be given by a professional physician for the condition of the appropriate treatment.