〔Abstract〕 Objective To explore the effect of Helicobacter pylori(Hp) on the expression of E-cadherin(CDH1) and the expression of CDH1 in gastric cancer tissues, so as to provide a theoretical basis for further exploring CDH1 in the role ofHpin gastric cancer. Methods Mongolian gerbils were gavaged withHp,and their gastric tissues were taken after March, December, and 24 months, and the expression of CDH1 was detected by immunohistochemical staining;Hpinfected gastric epithelial cells AGS,the samples were collected 24 hours later, and Western blot detected each Group CDH1 expression.TCGA and Kaplan-Meier Plotter databases were used to compare the expression differences of CDH1 in gastric cancer tissues and adjacent tissues and the prognostic analysis of CDH1 and gastric cancer; R language was used to perform KEGG enrichment analysis of CDH1 gene; human gastric cancer tissues were collected from the Department of Pathology of your hospital in 10 cases each of the tissue specimens and adjacent tissues, the expression of CDH1 was detected by immunohistochemical staining. Results Immunohistochemical staining results showed that the positive rate of CDH1 was 13.70%,13.20% and 22.90%,respectively, in the stomach tissues of Mongolian gerbils afterHpinfection at 3,12 and 24 months, and 0.04%,4.50% and 4.77%,respectively, in the control group, with statistical significance(P<0.05).The gray values of CDH1 protein expression inHp-infected AGS cells was higher than that in control cells, respectively, with statistical significance(P<0.05). A total of 449 cases with clinicopathological parameters and their corresponding CDH1 mRNA expression level were collected in TCGA gastric cancer database. The CDH1 mRNA expression level in adjacent tissues(76.36±0.48) was significantly lower than that in gastric cancer tissues(147.59±0.11),and the difference was statistically significant(P<0.05).Kaplan-meier Plotter database analysis showed that high expression of CDH1 in gastric cancer decreased the survival rate(P<0.05).KEGG enrichment showed that CDH1 expression was associated with gastric cancer, thyroid cancer, bladder cancer, endometrial cancer, melanoma and other tumors.The function of CDH1 was significantly enriched in bacterial invasion of epithelial cells and adhesion connection, and the pathways were significantly enriched in Apelin signaling pathway, Hippo signaling pathway and Rap1 signaling pathway.The positive rate of CDH1 in human gastric cancer tissues was 76.27%,which was higher than that in para-cancer tissues 45.68%,and the difference was statistically significant(P<0.05). Conclusion Hpinfection causes the increase of CDH1 expression level, which may be one of the reasons thatHpcauses gastric cancer.