The obstruction of food passage in the stomach is due to lesions such as ulcers or cancerous tumors. It can be divided into two main categories: incomplete obstruction and complete obstruction. Pyloric obstruction is one of the common complications of gastric and duodenal ulcers and can occur in the recent (i.e., active) or late stage of ulcer disease. Blood chemistry shows lower than normal sodium, potassium and chloride, increased carbon dioxide binding capacity and pH, high partial pressure of carbon dioxide, and hypokalemic alkalosis. Non-protein nitrogen or urea nitrogen is also higher than normal due to low urine output. Due to long-term starvation, hypoproteinemia may occur. If the anemia is severe and the stool is positive for occult blood, the possibility of malignant ulcer should be considered. Gastric fluid examination, benign ulcer disease gastric fluid acidity is high, generally in the range of 50 to l00mmol/h. If there is a lack of hydrochloric acid in the gastric fluid, further cytological examination and other tests should be done to exclude tumors. 2.X-ray In addition to the huge gastric bubble seen under fluoroscopy, barium X-ray gastrointestinal imaging should be done after gastric lavage. The enlarged stomach and difficulty in emptying can be clearly seen (Figure 1). In the case of pyloric spasm, temporary expulsion of the gastric contents during longer observation may be seen with pyloric relaxation. Pyloric relaxation is usually observed after atropine or 654-2 injection and is therefore easily distinguished, but pyloric stenosis due to mucosal edema and scar contracture is difficult to distinguish on radiographs. If the pyloric obstruction improves after a period of medical treatment, the presence of edematous factors can be indicated. In addition, the niche of ulcer or deformation of the duodenal jug abdomen can be seen, which is also 80% to 85% reliable for identifying benign or malignant ulcers. 3.Gastroscopy Fiberoptic gastroscopy can reveal different pathological changes such as pyloric spasm, mucosal edema or mucosal prolapse, and scarring stenosis, and can reveal the size, location and shape of the ulcer. In cases of suspected malignancy, a biopsy is required. Therefore, gastroscopy can provide an exact diagnostic basis for the etiology of pyloric obstruction. 4.Saline load test Firstly, the accumulated contents of the stomach will be aspirated, then 700ml of saline will be injected within 3~5min, and then saline will be aspirated out of the stomach after 30min. If the aspiration is less than 200ml, it means that there is no pyloric obstruction; if the aspiration is more than 350ml, it is considered that there is obstruction.