It is a common and safe treatment method to close the proximal single-lumen colostomy after sigmoid colon rupture, and the second-stage anastomosis time is generally 3 months to half a year later. The possible causes of stoma necrosis in the first operation are: 1. Proximal circulation is too short; 2. The fistula is too small, which oppresses the intestinal fistula; 3. Too many free blood vessels in mesentery of intestinal loop lead to poor blood circulation. There are obvious signs of necrosis, such as blackening, which should be handled in time to avoid fistula retraction. Causing abdominal cavity pollution. If the time is close to the second-stage operation, the second-stage anastomosis can be performed after intestinal preparation; If there is still a long time before the second-stage operation, the second-stage anastomosis should be carried out in time with active preoperative preparation. According to our experience, there are few cases of intestinal leakage after active intestinal preparation before and during operation. Of course, it is necessary to clarify the cause of sigmoid fistula in the early stage and rule out the possibility of tumor so as to deal with it together during operation.