The invention belongs to the field of genetic engineering and tumor medicine, and particularly discloses an SNP marker and kit for screening out and diagnosing a gastric cancer high-risk group. The SNP marker is a combination of rs2274223, rs13042395 rs7447927, rs1642764 rs35597309, rs10074991, rs2294693, rs4072037, rs10931936, rs13016963, rs10201587, rs7578456, rs9288318, rs1801133 and rs1048943.The invention further discloses a kit for screening out and the gastric cancer high-risk group. The SNP marker combination can be used for early evaluating and large-scale screening of the gastric cancer, is high in detection success rate and technical reproducibility, defines the gastric cancer high-risk group to the maximum extent, makes the early gastric cancer detection rate reach 71.4%, andprovides an important basis for screening out the gastric cancer high-risk group and evaluating the disease risk.