Analyzed the relationship between 568 site A/G polymorphism in mucin 1(MUC1) gene in a population from Liaoning Province and susceptibility to gastric cancer. Sequence specific primers-polymerase chain reaction(PCR-SSPs) were performed to analyze the genotype of the A/G polymorphism in its 568 site of exon 2 for 138 gastric cancer cases and 131 normal ones tested, and ELISA was performed to test IgG antibody of H. pylori. We found that the distribution frequency of AA, AG, GG three genotypes were 73.3%, 22.1%, 4.6%, respectively. The frequency of AA genotype was statistically higher in the gastric cancer (GC) group compared to the control group(P=0.03), moreover, individuals with the MUC1 AA genotype increased 1.92 fold risk for gastric cancer. And compared with subjects carrying both AG+GG genotype and H. pylori-IgG negative, there was an obviously increased risk of developing gastric cancer for those who carried both AA genotype and H. pylori-IgG negative, both AG+GG genotype and H. pylori-IgG positive, and both AG+GG genotype and H. pylori-IgG negative, but there were no significantly differences between the every two of the latter three. Our results indicated that there was a relationship between MUC1 A/G polymorphism and susceptibility to gastric cancer. And there were probably no statistically interaction between the 568 site A/G polymorphism in MUC1 and H. pylori infection in the occurrence and development process of gastric cancer.