The lower end of the esophagus is covered with abnormal columnar epithelium, called Barrett’s esophagus. It is widely believed to be acquired and is closely associated with reflux esophagitis with the possibility of adenocarcinoma, first described by Norman Barrett in 1950. Clinically, acidic gastric fluid from gastroesophageal reflux and alkaline intestinal fluid reflux after total gastrectomy have been found to cause mucosal damage to the lower esophagus, with columnar epithelial migration. Two factors that reduce the contractility of the lower esophageal sphincter and decrease the clearing function of the esophagus after the onset of reflux esophagitis also contribute to the formation of Barrett’s esophagus. The reflux contents, including one or more of gastric acid, pepsin, pancreatic enzymes, and bile acids, contribute to esophageal squamous epithelial metaplasia in GERD patients. Disruption of the squamous epithelium is followed by re-epithelialization of the gastric columnar epithelium in the cardia towards the cephalic end to the damaged area of the esophagus. In other rare cases, Barrett’s esophagus may occur as a result of corrosive burns to the esophagus or damage to the esophageal mucosa during prolonged application of anticancer chemotherapy. The causal relationship between esophageal motor dysfunction and columnar epithelial esophagus is not fully understood. The possibility of cancerous esophageal columnar epithelium has been identified during long-term follow-up.