The white blood cell count is increased, but not high in severe disease or when the organism is unresponsive, and only an increased proportion of neutrophils or toxic granules are present. The abdominal X-ray shows signs of intestinal paralysis such as widespread distention of the intestinal cavity and multiple small gas-fluid surfaces; the presence of free gas under the diaphragm is seen in most cases of gastrointestinal perforation, which is diagnostically important. The presence of free gas can be shown in patients who are weak or cannot stand for fluoroscopy due to shock, i.e., side-lying films can be performed. Differentiation: 1, acute intestinal obstruction Most acute intestinal obstruction has obvious paroxysmal abdominal colic, hyperacusis, abdominal distension, but no sure pressure pain and abdominal muscle tension, easy to distinguish from peritonitis. However, if the obstruction is not lifted, the intestinal wall is edematous and bruised, and the intestinal peristalsis is changed from hyperactivity to paralysis, the sounds may be weakened or disappear clinically, which is easily confused with peritonitis causing intestinal paralysis. In addition to careful analysis of symptoms and signs, and through the abdominal radiographs and close observation to distinguish, if necessary, need to make a caesarean section to clear. 2, acute pancreatitis edematous or hemorrhagic necrotizing pancreatitis have symptoms and signs of peritoneal irritation of varying severity, but not peritoneal infection; in differentiation, elevated serum or urinary amylase has important significance, and amylase values measured from the peritoneal puncture fluid can sometimes confirm the diagnosis. 3, intra-abdominal or retroperitoneal blood accumulation Various etiologies cause intra-abdominal or retroperitoneal blood accumulation, which can present clinical phenomena such as abdominal pain, abdominal distension, and diminished bowel sounds, but lack of signs such as pressure pain, rebound pain, abdominal muscle tension. Abdominal radiographs, abdominal puncture and observation can often clarify the diagnosis. 4, other urinary tract stone disease, retroperitoneal inflammation, etc. are due to their own characteristics, as long as the detailed analysis, the diagnosis is not difficult.