Highly dilated duodenum is one of the clinical symptoms of acute jejunal input collaterals obstruction in gastrojejunal input collaterals syndrome, and is also one of the causes of acute gastric dilatation. The duodenum is the shortest, largest, deepest and most fixed segment of the small intestine, with a length of 20-25 cm and a diameter of 4-5 cm. The pancreatic duct and the common bile duct both open in the duodenum. Therefore, it receives both gastric juice and pancreatic juice and bile injection, so the digestive function of the duodenum is very important. The shape of duodenum is “C” shaped, including the head of pancreas, and it can be divided into four parts: upper part, lower part, horizontal part and ascending part. So what are the diagnosis methods of high duodenal dilatation? Here is a brief introduction. Highly dilated duodenum diagnostic method 1, manifested as fullness in the upper middle abdomen after a full meal or postprandial jet vomiting, as well as erratic, nausea and other indigestion symptoms. 2, the diagnosis of this disease requires a barium meal examination of the stomach and intestines, which shows that the first and second part of the duodenum is dilated and has repeated strong retrograde peristalsis, and the barium can flow back into the stomach. If the swallowed barium cannot be emptied from the duodenum after 2-46, it indicates the presence of obstruction. If there is a neatly shaped oblique pressure mark and barium passage obstruction in the transverse or ascending part of duodenum, it indicates the possibility of superior mesenteric artery compression syndrome; if the patient takes prone or left side lying position, duodenal retention disappears, and the diagnosis of this syndrome can be more confirmed. 3.If necessary, aortography and barium meal can be performed at the same time, which can show the relationship between duodenal compression and superior mesenteric artery.