There are many possible causes of abdominal pain in children, and some of the more complex ones are often difficult to diagnose. Therefore, when a child with abdominal pain comes to the doctor, in addition to a detailed medical history, the doctor will do some selective tests to help confirm the diagnosis according to the suspected disease. First, the doctor will do the necessary physical examination, which includes visualization, auscultation, percussion, and palpation of the abdomen. In addition, skin bleeding spots, petechiae, jaundice, cardiopulmonary examination, groin and anal finger examination will be observed. Next, some necessary laboratory tests are selected, such as routine blood, urine and fecal tests, serum and urine amylase, H. pylori serum antibody and 13-carbon breath test, etc. For suspected peritonitis, internal bleeding, abdominal abscess and certain abdominal masses, diagnostic puncture is feasible, and routine smear, bacterial culture or pathological examination of the puncture material is performed. Some patients also need some imaging examinations to make a clear diagnosis. x-ray examinations: chest and abdominal fluoroscopy, routine radiographs, air enema and barium enema can be chosen as needed. In addition, ultrasound, endoscopy, CT, magnetic resonance and nuclear scan examination have good diagnostic value and should be reasonably selected for application according to the condition. For children with suspected myocarditis or cardiomyopathy, electrocardiogram should be performed. Finally, parents should be reminded that it is best for their children to go to the hospital on an empty stomach on the day of the visit, as many tests require an empty stomach.