Objective:To investigate the expression and distribution of aquaporin4(AQP4) in gastric carcinoma tissue and analyze its clinical significance. Methods:The gastric carcinoma tissues were obtained and the expression and distribution of AQP4 in carcinoma and normal stomach tissues were examined by immunohistochemistry,RT-PCR and Western-blot analysis respectively. Results:AQP4 was expressed mainly in the normal gastric tissue basal side of parietal cell and principal cell and absent in carcinoma tissues. Conclusion:AQP4 is mainly expressed in normal stomach tissue and not found in carcinoma tissues.