Objective:To investigate the expression difference of aquaporin-3(AQP3) in each stage of gastric adenocarcinoma(GAC),and the relationship with lymph node metastasis. Methods:Collecting 80 cases of gastric adenocarcinoma tissue and corresponding nontumor tissue,the AQP3 expression of mRNA and protein in each sample were detected by quantitative real time polymerase chain reaction(qPCR) and Western blot. Then,the relationship between AQP3 expression and clinicopathologic characteristics of the patients was analyzed. Results:The different expressions of AQP3 in each stage of GAC (T1,T2,T3,T4),according to UICC(2010),had effects on lymph node metastasis;The expression of AQP3 in tumor tissue with lymph node metastasis was higher than that without lymph node metastasis. Conclusion:The overexpression of AQP3 in GAC might stimulate the occurrence of lymph node metastasis. The overexpression of AQP3 can be taken as a biomarker of GAC prognosis and metastasis. AQP3 might be a therapy target of gastric adenocarcinoma.