Objective : To investigate the expression of N6-methyladenosine modification ( m6 A) and related en- zymes FTO，METTL3 and YTHDF2 in gastric epithelial cells infected with Helicobacter pylori (Hp) ，and to analyze its expression and clinical significance in gastric cancer by using online websites． Methods : Gastric epithelial cells GES-1 and AGS were infected with Hp GZ7 strain，and the multiplicity of infection was 30 ∶ 1．Total RNA and total protein were collected after infecting 24 h，and the m6 A modification level of total RNA was detected by RNA dot hybridization．The mRNA and protein expressions of FTO ，METTL3 and YTHDF2 were detected by q-PCR and Western blot．The expression difference of FTO，METTL3 and YTHDF2 in gastric cancer tissues and normal tissues and their expression in Stage classification were analyzed by GEPIA，and the relationship between the expression of FTO，METTL3 and YTHDF2 and prognosis was analyzed by Kaplan-Meier Plotter. Results : Compared with the un- infected group，the m6 A modification level of total RNA in both Hp-infected GES-1 and AGS cells significantly de- creased，the mRNA and protein expression levels of FTO increased，and the mRNA and protein levels of METTL3 and YTHDF2 decreased，with statistical significance (P＜0. 05) ．The expression level of FTO in gastric cancer tis- sues was higher than that in normal tissues，with statistical significance (P＜0. 05) ，YTHDF2 was higher than that in normal tissues，with no statistical significance，and the expression level of METTL3 was lower than that in nor- mal tissues，with no statistical significance．Patients with high expression of FTO and METTL3 had a lower survival rate，while patients with high expression of YTHDF2 had a higher survival rate．The expression of FTO was signifi- cantly correlated with Stage classification (P＜0. 05) ，while the expression of METTL3 and YTHDF2 was not sig- nificantly correlated with Stage classification． Conclusion Hp infection can change the level of m6 A and the ex- pression of related enzymes FTO，YTHDF2 and METTL3，suggesting that m6 A methylation may play a role in the occurrence and development of Hp-induced gastric cancer.