After rectal cancer surgery, outpatient follow-up is usually every three months, half a year or one year to check blood routine, tumor markers, blood biochemistry, abdominal CT and colonoscopy. The prognosis of rectal cancer is related to its clinicopathologic stage, location and treatment measures, etc. Therefore, in order to improve the survival rate of rectal cancer, it is necessary to closely follow up the patients to check their therapeutic efficacy and changes in indicators. Usually, within 2 years after surgery, outpatient review is conducted every three months to improve blood routine, blood biochemistry, tumor markers and other blood tests, and abdominal CT and colonoscopy must be reviewed every 1 year. Within 2 to 5 years after surgery, the review can be done once every six months; after 5 years, the review may be done once every 1 year, and lifelong follow-up is required. The purpose of review is to see if the treatment plan is effective and if the tumor has recurred, so that the treatment plan can be changed in time. Therefore, postoperative patients must have regular follow-ups. All of the above items and time for follow-up are for those who have no discomfort after surgery, but if there are symptoms such as intestinal obstruction after surgery, the items and time for follow-up will be different. Therefore, patients should follow the instructions.