The steps of small colonoscopy are divided into cleaning the intestinal tract, oral entry examination and anal entry examination. 1. Bowel cleansing: laxatives can be taken according to the doctor’s instructions to completely expel the feces from the bowel, so as to facilitate the observation of whether there is any abnormality in the bowel. 2. Oral microscopy: the mirror enters the stomach through the mouth and then reaches the duodenum, then enters the jejunum, extends along the jejunum step by step and probes whether there is any abnormality in the intestines, and when it reaches the farthest point where it can no longer go forward, it will make a good mark. 3. Anal entry: the mirror enters from the anus, passes through the colon first, then enters the small intestine, extends upward along the small intestine and explores whether there is any abnormality in the intestinal tract, and completes the examination of the whole small intestine after reaching the marking point. Small bowel examination will produce certain damage to the digestive tract, after the examination, pay attention to diet, abnormal digestive function or physical discomfort, can go to the hospital for examination and treatment, so as not to delay the condition.