Objective: To investigate the effects of Helicobacter pylori (H.pylori) on the proliferation of GES-1 cells and the expressions of S100A8 and S100A9 in human gastric epithelial cell line GES-1. Methods: H. pylori were co-cultured with GES-1 cells at different infection plural (muhiplieity of infection (MOI) 50∶1, 100∶1, 200∶1), then the cells and cell culture supernatants were collected. The proliferative activity was detected by cell counting kit 8 (CCK-8) methods. The expression of S100A8 and S100A9 at mRNA level was determined by reverse transcription polymerase chain reaction (RT-PCR). The levels of S100A8 and S100A9 proteins and tumor necrosis factor-alpha (TNF-α) in cell culture supernatants were measured by enzyme linked immunosorbent assay (ELISA). T test and Pearson method were performed for statistical analysis. Results: The negative control group was taken as the baseline, the proliferation rates of GES-1 cells of the H. pylori multiplicity 50∶1 group, 100∶1 group and 200∶1 group were (105.51±4.78)%, (168.97±11.29)% and (64.05±10.11)%, respectively. There was no statistically significant difference in the proliferation rate of GES-1 cells between H. pylori multiplicity 50∶1 group and negative control group (t=0.69, P=0.51). The proliferation rate of GES-1 cells of the H. pylori multiplicity 100∶1 group was higher than that of the negative control group, and the difference was statistically significant (t=10.63, P<0.01). The proliferation rate of GES-1 in the H. pylori multiplicity 200∶1 group was lower than that of the negative control group, and the difference was statistically significant (t=-5.54, P<0.01). The expression of S100A8 and S100A9 at the mRNA level in the H. pylori multiplicity 200∶1 group was 0.31±0.21 and 8.66±4.08, respectively, which were higher than those of the negative control group (0.06±0.05 and 0.08±0.08), and the differences were statistically significant (t=10.20 and 6.89, both P<0.05). The expressions of S100A8 at the protein level of H. pylori multiplicity 50∶1, 100∶1, and 200∶1 groups were (112.21±1.25) ng/mL, (120.39±1.61) ng/mL and (121.28±0.71) ng/mL, respectively; while the expression of S100A9 at the protein level were (179.43±2.44) ng/mL, (191.47±1.98) ng/mL and (201.80±2.06) ng/mL, respectively; and the expression of TNF-α levels were (285.52±3.64) ng/mL, (320.08±2.28) ng/mL and (350.97±2.90) ng/mL, respectively; which were all higher than those of the negative control group ((76.14±1.30) ng/mL, (161.35±1.31) ng/mL and (270.08±2.96) ng/mL, respectively), and the differences were statistically significant (t_S100A8=35.09, 43.06, 43.92, t_S100A9 = 11.13, 18.54, 24.90, t_TNF-α= 6.34, 20.54, 33.23; all P<0.01). The expressions of S100A8 and S100A9 at the protein level were positively correlated with TNF-α (r=0.92 and 0.95, both P<0.01). Conclusion S100A8 and S100A9 may be involved in the process of H. pylori induced proliferation disorder and inflammation in GES-1 cells.