Intestinal obstruction is a state in which the intestinal contents cannot function normally or are obstructed in their passage. According to the cause of obstruction, it can be divided into mechanical intestinal obstruction, dynamic intestinal obstruction and hemodynamic intestinal obstruction; according to the presence or absence of blood flow obstruction of the intestinal wall, it can be divided into simple intestinal obstruction and strangulated intestinal obstruction; according to the height of the obstruction site, it can be divided into high intestinal obstruction and low intestinal obstruction. When simple intestinal obstruction occurs, the peristalsis above the obstruction increases to overcome the obstruction of intestinal content passage. At the same time, the intestinal cavity is dilated by accumulation of fluid and gas, and the fluid mainly comes from the retained gastrointestinal secretion; the air swallowed, the gas diffused by blood into the intestinal cavity, and the gas produced by bacterial decomposition of intestinal contents make a large amount of gas accumulation in the intestinal cavity. The lower the site of intestinal obstruction and the longer the time, the more obvious the dilatation of the intestinal canal. Below the obstruction, the intestinal canal is atrophied, empty or only a small amount of feces is accumulated. In acute intestinal obstruction, the intestinal canal dilates rapidly, the intestinal wall thins, and the pressure in the intestinal lumen rises, which can lead to impaired blood flow in the intestinal wall at a certain level. The initial manifestation is obstruction of venous reflux, depression of blood in the capillaries and small veins of the intestinal wall, and congestion, edema and thickening of the intestinal wall. As a result of hypoxia, capillary permeability increases, and there are bleeding spots on the intestinal wall, and bloody exudate leaks into the intestinal and abdominal cavities. With the development of blood flow disorders, arterial blood flow is subsequently blocked and thrombosis occurs, leading to ischemic necrosis of the intestinal tube. The main clinical manifestations of intestinal obstruction include abdominal pain, vomiting, abdominal distension, and cessation of defecation and exhaustion, and generally the higher the obstruction site, the earlier vomiting appears. Depending on the complications, more complex clinical manifestations may occur. With the wide application of CT and the progress of CT technology, especially the application of spiral CT, CT plays an increasingly important role in the diagnosis of intestinal obstruction, which can show the thickening of the intestinal wall and abnormal blood supply to the intestinal wall that cannot be shown by abdominal plain film and barium enema, and whether there are pathological changes in the intestinal mesentery and abdominal cavity, etc. CT has many advantages in defining the cause of obstruction, the site of obstruction and determining strangulation, and is important for observing the changes of the disease and guiding the treatment. It is important to observe the changes of the disease and guide the treatment. Therefore, CT can be the first choice of examination method for intestinal obstruction in hospitals with conditions, and the timing of CT examination is best chosen before gastrointestinal decompression, which can help to correctly determine the site and degree of obstruction. For cases where it is not clinically clear whether there is intestinal obstruction or incomplete obstruction, the method of oral administration of 2-4% iodine-containing contrast agent can be adopted. Enhancement scan has a very important value for diagnosis and should be done as a routine examination of intestinal obstruction.