Objective: To study the rule of development of early cancer of gastric cardiac in vivo. Methods: A prospective cohort was held in the high incidence area of cancer of esophagus and stomach in china. One hundred and six persons were examined regularly by endoscopy to observe the change of pro-cancer lesions of gastric cardiac by taking biopsy specimen. All specimens were diagnosed through normal pathological process. Results: The 106 subjects were examined twice in 1998 and 2002. Of 8 normal persons, 3 stayed normal, 4 turned to chronic gastritis, 1 developed early gastric cardiac cancer. Of 61 persons with chronic gastritis, 11 were observed to have gland atrophy, 4 with mild atypical hyperplasia, and 2 with highly atypical hyperplasia. Of 9 subjects showing atrophic chronic gastritis, 5 revealed no change, and 4 became chronic gastritis. Of 22 subjects who revealed mild atypical hyperplasia, 17 resolved, 4 showed no change, and 1 advanced to highly atypical hyperplasia. One person with highly atypical hyperplasia reverted to mild atypical hyperplasia. Of 5 subjects with early gastric cardiac cancer without any treatment, 1 became advanced cancer, 1 still stayed in early cancer stage, 3 turned to atypical hyperplasia. Conclusion: 1. The development of early cancer of gastric cardia would proceed through the stages of chronic gastritis, gland atrophy, and atypical hyperplasia. 2. The early cancer and pre-cancer lesions of gastric cardia is reversible, though possessing malignant possibility.