1.Endoscopy The upper gastrointestinal endoscopy is the main method to confirm the diagnosis of peptic ulcer. Under direct endoscopic view, peptic ulcers are usually round, oval or linear, with sharp edges and basically smooth, covered by grayish or grayish-yellow mossy membrane, and the surrounding mucosa is congested, edematous and slightly elevated. 2.Barium X-ray examination The main X-ray image of peptic ulcer is the niche or niche shadow, which is caused by the filling of the depressed part of the ulcer with barium suspension. In frontal view, the niche shadow is round or oval with neat edges. An annular translucent area is formed due to the inflammatory edema around the ulcer. 3.Detection of HP infection The detection methods of HP infection are broadly divided into four categories: ① direct examination of HP from gastric mucosal tissue, including bacterial culture, tissue smear or section staining microscopic examination of bacteria; ② determination of gastric urease activity by urease test, respiratory test, gastric fluid urea nitrogen test, etc.; ③ serological examination of anti-HP antibodies; ④ application of the multiplex enzyme chain reaction (PCR) technique to determine HP- DNA. 4. Gastric fluid analysis The average basal acid excretion (BAO) was 2, 5 and 1, 3 mmol/h for normal males and females, respectively, (0-6 mmol/h), and 5, 0 and 3, 0 mmol/h for male and female duodenal ulcer patients, respectively. when BAO >10 mmol/h, it often suggests the possibility of gastrinoma. The maximum acid excretion (MAO) after pentagastrin injection at 6 μg/kg is often more than 40 mmol/h in patients with duodenal ulcer. Since the results of gastric fluid analysis in various upper gastrointestinal diseases have overlapping gastric acid amplitude with normal subjects, the diagnosis of ulcer disease is only for reference.