Patients with CAG can have no obvious clinical manifestations, so the exact prevalence of the disease in the population is not fully known, leading to a paucity of epidemiological data on CAG and a lack of comparability due to inconsistent diagnostic criteria (gastroscopy or serology) used in various studies. However, it is certain that the incidence and prevalence of CAG varies among populations in different regions and is highly variable. Foreign data show that the prevalence of CAG and intestinalization is also relatively high in East Asia, Eastern Europe and South America, where the prevalence of gastric cancer is high. The WHO survey found that the prevalence of CAG in people aged 20-50 years was only about 10%, while the prevalence in people aged 51-65 years was more than 50%. Based on the epidemiological findings that the prevalence of chronic atrophic gastritis increases with age, it is also believed that gastric mucosal atrophy is a degenerative lesion and a “semi-physiological” phenomenon. In China, the detection rate of CAG accounts for 7.2-13.8% of the total number of patients examined by gastroscopy, and up to 28.1% in areas with a high incidence of gastric cancer.