The nature of abdominal pain in clinical cases of visceral perforation is simply described as knife-like pain. The most common perforation of intra-abdominal organs is mainly peptic ulcer, including gastric ulcer or duodenal ulcer perforation, which is clinically called knife-like pain because of the intense pain caused by the inflow of gastric juice into the abdominal cavity after perforation, resulting in chemical peritonitis. If not treated promptly at this time, bacterial infection can develop secondary to the peritonitis, causing diffuse peritonitis or even toxic shock, which can seriously endanger the patient’s life. Treatment requires timely fasting, gastrointestinal decompression and surgery.