Autoimmune gastritis belongs to chronic atrophic gastritis, a chronic gastritis in which the gastric mucosa is atrophically altered by autoimmunity, and the extent of gastric mucosal atrophy is mainly located in the gastric body. In addition, there is another type of chronic atrophic gastritis called type B gastritis, which is multifocal atrophic gastritis. The key to the treatment of autoimmune gastritis is close follow-up, with regular review of electronic gastroscopy and pathology as prescribed by the doctor. When the patient’s pathological examination clearly shows severe atypical hyperplasia of gastric mucosa, that is, heterogeneous hyperplasia, it indicates precancerous lesion of gastric cancer, which requires timely preventive surgery and endoscopic gastric mucosal resection.