Normal esophageal squamous mucosa coating layer, such as local squamous mucosa was columnar epithelium, is called Barrett esophagus. Early in 1805 Schmidt in his essays first described in the esophagus ectopic gastric mucosa island, but did not cause the medical attention. Until the 1950 Barrett Barett) in Britain (the surgical magazine reported lower esophageal mucosal coating columnar epithelium lesions, and in 1957 and made a detailed description on the medical attention, caused the esophagus. Then the author says the columnar mucosa, such as Barrett esophageal squamous esophageal. Clinic for Barrett's esophagus) is not uncommon.barrett, upper rate (1.4% ~ clans report), average 16.3%respectively.