The development of atrophic gastritis to gastric cancer requires two stages of intestinal metaplasia and heterogeneous hyperplasia in between, which is generally long, taking at least several years or even decades. Atrophic gastritis is the atrophy of epithelium and glands of gastric mucosa, the number of glands decreases, and the gastric mucosa becomes thin, which can be divided into mild, moderate, and severe according to the degree of glandular atrophy. Mild chronic atrophic gastritis is partially reversible with aggressive drug therapy; moderate and severe chronic atrophic gastritis are relatively difficult to treat. About 6% of those with chronic atrophic gastritis who develop intestinal epithelial hyperplasia may develop gastric cancer. The more extensive the intestinal metaplasia, the higher the risk of carcinogenesis. It usually takes a long time for atrophic gastritis to develop cancer, and the exact length of time needs to be analyzed in the context of one’s own condition. Once the diagnosis of atrophic gastritis is confirmed, especially if it is accompanied by intestinal metaplasia, it should be taken seriously and treated actively.