Objective To systematically evaluate the association between Helicobacter pylori （H.pylori） infection and Alzheimer disease （AD） by using Meta-analysis. Methods The databases were searched for casecontrol studies and cohort studies on the association between H.pylori infection and AD， including PubMed， Embase， Cochrane Library， Web of Science， CNKI， Wanfang Database， VIP database， and CBM. The search was limited to January 2000 through November 2022. Two researchers screened， extracted， and evaluated the quality of literature independently. Meta-analysis was conducted using RevMan 5.3 software. Results A total of 15 studies were included： 9 case-control studies (n=1 404) and 6 cohort studies （n=7 893）. Meta-analysis showed that the infection rate of H.pylori of AD group was higher than that of control group ［OR=1.58， 95%CI （1.21-2.06）， P＜ 0.01］； the content of HP-IgG antibody in AD patients was higher than that in control group ［MD=6.14， 95%CI （2.99-9.29）， P＜ 0.01］； the Minimum Mental State Examination score in AD patients was lower than that in control group ［MD=-9.89， 95%CI （-14.04- -5.74）， P ＜ 0.01］. The incidence of AD in patients with confirmed H.pylori infection was greater than that in normal controls ［RR=1.33， 95%CI （1.11- 1.59）， P ＜ 0.01］. All the differences were statistically significant. Conclusions Current limited evidence suggests a close link between AD and H.pylori infection. For AD， H.pylori plays an important role in both etiology， progression and prognosis of AD.