Abstract: 【Abstract】Objective To study the helicobacter pylori（Hp）infection and the expression of hypoxiainducible factor-2α(HIF-2α）and ABCG-2 in gastric cancer tissues and discuss Hp infection in the initiation and development of gastric cancer as well as chemotherapy resistance induction. Methods Hp infection was identified by rapid urease test and immunocytochemistry in gastric cancer（n=60）and chronic gastritis（n=45）. Immunohistochemistry was used to detect the expression of HIF-2α and ABCG2 proteins in gastric cancer tissue. Results Hp positive rate of gastric cancer group（67.3％） was higher than that of chronic gastritis group（45.2％）with statistic significance（P=0.029）. Hp infection was correlated with the depth of infiltration and lymph node metastasis（P＜0. 05），but not with gender，age，tissue differentiation and distant metastasis（P＞0.05）. The positive rate of HIF2α protein in Hp（+）and Hp（-）gastric cancer tissues were 81.1％ and 50.0％. Hp infection and the expression of HIF-2α protein in gastric cancer tissues was positively correlated（r=0.321，P=0.017）. The positive rate of ABCG-2 protein in the Hp（+）and Hp（-）gastric cancer tissues were 86.5％ and 55.6％. Hp infection and the expression of ABCG-2 protein in gastric cancer tissues was positively correlated（r=0.342，P=0.011）. The expression of HIF-2α was positively correlated with ABCG-2 in Hp（+）gastric cancer tissue（r=0.604，P＜0.0001）. Conclusion Hp can stimulate the expression of HIF-2α and ABCG-2 in gastric cancer tissues by activating HIF-2α-ABCG-2 pathway，suggesting that Hp may play an important role in inducing stem cellularization of gastric cancer cells and chemotherapy resistance.