In the progression of chronic inflammation to gastric cancer, chemosis, atrophy and heterogeneous hyperplasia are considered as precancerous states of the stomach. Atrophic gastritis is only a precancerous state and does not necessarily transform into cancer under effective treatment. There is a gradual development process of gastric cancer formation. If patients have atrophic gastritis, they must be reviewed regularly, and if early gastric cancer is found, it can be treated by microscopy. The specific time needed to transform into cancer cannot be determined. When the condition is mild, active treatment and attention to life and diet habits, etc., the time needed to transform into cancer will be longer or even not; however, if the treatment is not timely or attention is not paid to precautions in life, it may aggravate or trigger cancer to advance. Generally, if atrophic gastritis recurs for a long time, the chance of cancer will also increase. Mild chronic atrophic gastritis may be reversed with some medications, while moderate and severe chronic atrophic gastritis are more difficult to treat. Especially for people with weaker constitution, the possibility of cancer tends to be higher. Patients with atrophic gastritis should pay attention to the dietary rules, food should be diversified, avoid partial diet, pay attention to supplement a variety of nutrients; do not eat moldy food; eat less smoked, pickled, nitrate and nitrite rich food, eat more fresh food; avoid the aggravation of atrophic gastritis, so that the cancer speed up. Therefore, atrophic gastritis may not necessarily transform into cancer under active and effective treatment, and the time to turn into cancer varies from person to person. Patients should go to regular hospitals for timely treatment under doctors’ guidance and regular review in order to keep abreast of the development of the disease.