To demonstrate candidate single nucleotide polymorphisms that might affect susceptibility to gastric adenocarcinoma as well as their potential mechanisms and pathway hypotheses, we performed a genome-wide association study dataset of gastric adenocarcinoma. Our study included 472,342 single nucleotide polymorphisms from 2766 cases of gastric cardia adenocarcinoma cases and 11,013 subjects from north central China as control groups. The identify candidate causal SNPs and pathways (ICSNPathway) analysis was employed to identify 13 candidate single nucleotide polymorphisms, nine genes, and 15 pathways. The top three candidate SNPs were rs3765524 (-log10(p) = 8.556), rs2274223 (-log10(p) = 8.633), and rs2076472 (-log10(p) = 3.205). The strongest mechanism involved the modulation of rs4745 and rs12904, thereby affecting their regulatory roles in ephrin receptor binding (p = 0.001; FDR = 0.005). The second strongest hypothetical biological mechanism was that rs932972 and rs1052177 alters the regulatory role of the glycolysis pathway (p < 0.001; FDR = 0.013). The most significant pathway was the regulation of the ephrin receptor binding pathway, which involved EFNA1, TIAM1, EFNA5, EFNB2, and EFNB3.