Abstract: OBJECTIVE To investigate the correlation between gastric cancer CDH1 gene methylation and Helicobacter pylori infection in patients with gastric cancer, so as to provide reference for clinical practice. METHODS A total of 62 cases of gastric cancer patients from our hospital Jan. 2014 to Dec. 2015 were chosen as research subjects, selecting gastric tissue as the observation group, the normal gastric stomach tissue as the control group, taking PCR the way to measure in both groups CDH1 gene methylation, whose expression of cases observed correlation with H. pylori infection. SPSS 19.0 was used for data analysis. RESULTS The positive rate of methylation in gene CDH1 was 72.6%, significantly higher than 11.3% in control group (P<0.05); CDH1 gene methylation and expression in gastric cancer patients had correlation with age, tumor differentiation and lymph node metastasis and TNM staging, and the difference was significant (P<0.05). H. pylori CDH1 gene methylation positive rate was 90.5%, higher than H. pylori negative data 35.0%, and the difference was significant (P<0.05). CONCLUSION CDH1 gene methylation plays a key role in the development of gastric cancer, and its expression is closely linked with H. pylori infection.