AIM: To explore the correlation between Helicobacter pylori(H. pylori) infection and colorectal adenoma. METHODS: We continuously collected a total of 410 patients (74 of colorectal adenoma patients and 336 of normal control patients) in the endoscopy center of Renji Hospital Affiliated to Shanghai Jiao Tong University, all patients went through gastroscopy and colonoscopy within the same day. The difference of H. pylori infection rate between colorectal adenoma group and control group was compared. Then the colorectal adenoma group was divided into subgroups according to the number, maximum diameter and pathological type of adenomas. H. pylori infection rate of each subgroup was compared. Statistical analysis of t test and chi square test were used, and P<0.05 was considered statistically significant. RESULT: The infection rate of H. pylori in colorectal adenoma group and control group were 29.73% and 19.34% respectively, and the difference was statistically significant (P<0.05). H. pylori infection rate within each subgroup showed no significant difference (P>0.05), but stratified analysis according to the progressive layers compared with the control group were statistically significant (P<0.05). CONCLUSION: H. pylori infection is a risk factor and maybe a promote factor for colorectal adenoma.