The cardia e-g line usually refers to the gastroesophageal mucosal line, which refers to the junction of the gastric mucosa and esophageal mucosa. Normal gastric mucosal epithelium is single-layer columnar epithelium, and normal esophageal epithelium is complex flat epithelium. The esophagogastric mucosal line is the junction of esophagus and stomach, which is ring-shaped or toothed, and it is important to check the migratory area of this esophagus and stomach under gastroscopy, and this line can be determined according to the different colors of two kinds of mucous membranes, which is of great significance to identify Barrett’s esophagus and the location of tumors. This line is regulated by many kinds of nerves and hormones, and it is a good site for inflammation, varicose veins and tumors. During gastroscopy, it should be passed slowly to avoid damaging the mucosa of this line. If there is any abnormality in the stomach or esophagus, it is necessary to consult a doctor in time for a clear diagnosis and standardized treatment so as not to delay the condition.