Duodenal ulcers can be detected by gastroscopy. Gastroscopy has diagnostic significance for diseases of the esophagus, stomach and duodenum. After a detailed examination of the patient’s stomach body, the gastroscope can be passed through the pylorus into the duodenal area and the duodenum can be observed. Gastroscopy can not only confirm the diagnosis of duodenal ulcer disease, but also help determine the extent of the ulcer, the area of the ulcer, and if necessary, biopsies can be taken from the ulcer site for pathological examination to understand the progress of the patient’s condition. However, in some patients with duodenal ulcers, the ulcer is located at the junction of the bulb and the descending part, and the diagnosis cannot be fully made because this area is obstructed by vision. After the detection of duodenal ulcer disease should be treated with omeprazole and thioglycollate as soon as possible, and should also do a good job of dietary care to promote the recovery of duodenal ulcer.