Objective To analyze the clinical characteristic of autoimmune gastritis (AIG).Methods From January 1990 to April 2010,the clinical data of 55 AIG patients were retrospectively analyzed,which included hemoglobin,lactate dehydrogenase (LDH),α-hydroxybutyrate dehydrogenase (α-HBDH),gastrin,intrinsic factor antibody (IFA),parietal cell antibody (PCA),gastrointestinal endoscopy examination and 24-hour esophageal pH recording.Another 31 megaloblastic anemia (MA) patients were selected as control.Statistical analysis was performed by independent-samples t test.Results Among 55 AIG patients,49 patients were associated with MA,and three out of four cases were identified of IFA.About 43.8％ (21/48) patients were PCA positive.Before treatment,the levels of LDH and α-HBDH of AIG patients with MA were (1045.50±853.46)U/L and (853.71±824.23) U/L which significantly increased,than those of patients without MA [(166.67±41.03) U/L,(133.67±27.90) U/L],the differences were statistically significant (t=-4.665,-2.120,both P＜0.05),however there was no significant difference when compared with the control group [(1047.52±1028.31) U/L,(1050.23±1264.37) U/L,both P＞0.05)].A total of 46 patients underwent gastroendoscopy examination,63.0％ (29/46) patients had gastric body atrophy while gastric antrum not involved; 34.8％ (16/46) patients had neither gastric body nor antrum atrophy; seven patients gastric mucosal showed intestinal metaplasia and one patient showed intestinal metaplasia with atypical hyperplasia and 2.2％ (1/46) presented both the antrum and the body atrophy.Conclusions The levels of LDH and α-HBDH increased in AIG patients might be related with MA caused marrow in-situ hemolysis.IFA is recommended as a routine test for AIG.There is still some limitations of AIG diagnosis according to histopathological features of gastric endoscopy specimen.The clinical features should be taken into consideration.