Gastric ulcer is characterized by recurrent epigastric pain of a rhythmic nature, which hurts before meals and will be relieved after eating, accompanied by acid reflux, belching, burning, and noisy sensations. The main basis of barium meal examination of gastric ulcer is based on several aspects: 1. direct signs are niche shadow and concentration of mucosal folds; 2. indirect signs are spasm and irritation of the stomach wall. The definition of niche shadow is the retention of barium in the ulcer, which is papillary or semicircular in shape and protrudes into the lumen. When gastric ulcers are found, attention should be paid to identify benign and malignant gastric ulcers, mainly from four aspects: the shape and location of the niche shadow, the shape of the mouth and the surrounding mucosal periphery. The shape of the niche shadow, benign ulcers are round and oval in frontal view with smooth and neat edges, while malignant niche shadows are irregular in shape and can be stellate. The location of the niche shadow, such as the benign niche shadow protrudes outside the gastric contour, while the malignant niche shadow protrudes within the gastric contour. Around the niche shadow and in the mouth, benign mucosal edema can be manifested as mucosal lines, collar sign, narrow neck sign, mucosa concentrated toward the open niche shadow, and straight to the mouth. Malignant can be seen as a filling defect of the acupressure sign with irregular ring dikes and disruption of the folds. Changes in the nearby gastric wall, benign lesions are soft and peristaltic waves, malignant gastric wall is stiff, sheath straight, and peristaltic movement disappears.