Objective To investigate the incidence of heterotopic gastric mucosa in upper esophagus (HGMUE), and study the endoscopic manifestation and comorbidity of HGMUE.Methods A retrospective study was made among patients who underwent esophago-gastroduo-denoscopy and diagnosed with HGMUE from January 2019 to June 2020.Results Of the 51 326 patients who underwent EGD, 375 were diagnosed with HGMUE (0.73%). HGMUE are a velvety mucosa that is rosiness-orange in color, well-circumscribed in area, variable in quantity and size. Endoscopic complications include: gastroesophageal reflux disease with positive endoscopic image (n = 75, 20.00%) which included reflux esophagitis (RE, n = 44, 11.73%), Barrett’s esophagus (BE, n = 26, 6.93%), RE and BE coexists (n = 5, 1.13%); Erosive gastritis (n = 56, 14.93%); Polyps (n = 54, 14.40%) which included gastric polyps (n = 47, 12.53%) and duodenal polyps (n = 7, 1.87%). The forth was peptic ulcer (n = 42, 11.20%) which included duodenal ulcer (DU, n = 21, 5.60%), gastric ulcer (GU, n = 17, 4.53%), GU and DU coexists (n = 4, 1.07%); Malignancy (n = 9, 2.40%) which included gastric carcinoma (n = 3, 0.80%) and esophageal carcinoma (n = 6, 1.60%). HGMUE without endoscopic complications (n = 139, 37.06%).Conclusion Acid related diseases were common comorbidities of HGMUE. Since a relatively high prevalence of malignancy, especially esophageal malignancy was found as comorbidity of HGMUE, it could be a warning factor for malignancy.