Abdominal pain is a common clinical problem in pediatrics with a complex etiology, varying conditions, and a variable prognosis. The following system describes the clinical diagnostic ideas and principles of management of patients with abdominal pain. What are the common etiologies? (1) Acute inflammation of abdominal organs: such as gastroenteritis, acute necrotizing enterocolitis, acute pancreatitis, acute cholecystitis, acute appendicitis, etc. (4) inflammation of the peritoneum: mostly caused by gastrointestinal perforation and, to a lesser extent, spontaneous peritonitis (8) other: urticaria, angioneurotic edema, food allergy, food poisoning, etc. (2) Chronic abdominal pain (1) chronic inflammation of abdominal organs: such as chronic gastritis, peptic ulcer, inflammatory bowel disease (IBD), chronic cholecystitis, etc. (2) Chronic inflammation of peritoneum: such as tuberculous peritonitis. (3) Tumor compression infiltration: malignant tumors are predominant. (4) Chronic strain, torsion, adhesion of intra-abdominal organs, such as chronic gastric torsion, intestinal torsion, etc. (5) Functional diseases, such as functional dyspepsia, irritable bowel syndrome, intestinal spasm, etc. (6) chronic poisoning: uremia, lead poisoning, porphyria, etc. Judgment of abdominal pain: location (place, P): to identify the exact site of pain, the child can be asked to point out the site with a finger; quality (Q): sharp stabbing pain (such as injury) or diffuse pain that is difficult to locate (visceral pain); radiation (R): pain can radiate from the primary site to Severity (S): pain can be graded from 0 to 10 using a pain quantification scale; Timing/oncet (T): time of onset, duration, variation throughout the day, whether it decreases at night, frequency of episodes; Alleviating factors (A): any factor that reduces abdominal pain, such as body position A): any factor that worsens abdominal pain, such as body position, exercise (or less movement), medication; aggaravtingfactors (A): any factor that worsens abdominal pain, such as body position, exercise, eating; associated symptoms (A): include black stool, blood in stool, vomiting, nausea, rash, diarrhea, fever, and weight loss. Associated symptoms can help to speculate possible diseases What tests can be done for abdominal pain: 1. Gastroscopy: can clarify gastroduodenal ulcers, obstructive strictures, tumors and active bleeding foci; 2. Colonoscopy: can clarify colon and terminal ileal diseases 3. Small intestine microscopy: can find jejunal lesions; 4. Laparoscopy: is valuable for the diagnosis of abdominal pain and helps to distinguish appendicitis from other causes of lower abdominal pain 5.X-ray: abdominal standing film: can observe the presence of subdiaphragmatic free gas caused by gastrointestinal perforation, retroperitoneal pneumonia, the presence of stepped liquid flat segments or inflated and enlarged intestinal loops of intestinal obstruction, kidney and ureteral stones or pancreatic stones, etc. Gastrointestinal barium meal imaging: gastrointestinal ulcers, diverticula, tumors, polyps are; 6.B ultrasound: liver, spleen, gallbladder, pancreas, appendix, kidneys, uterus and ovaries and other organs, lymph nodes and blood vessels, ascites; 7.CT: superior to the first two, a safe, non-invasive, fast and effective test to evaluate acute abdomen 8, MRI: the examination is more time consuming and usually has less diagnostic value than CT for abdominal pain.