Abstract: To study the relationship bwtween the glutathione s-transferase gene deletion,environment al factors and susceptibility to gastric carcinoma,A case-control study were conducted to screen the environmental risk factors of gastric cancer.A total of 41 pairs of cases and controls were matched on sex,age and nationality.Blood cells were detected for GST M1 genotype by polymerase chain reaction.Results The GsTM1 gene deletion rate ing astric carcinoma group was 58.5%and that in the contr ol group was 34.1%,they being significantly different statistically(χ²=3.972,p<0.05,OR=2.724).Exposing to the env ironmental factors(such as smoking,consumption of preserved eggs,salty eggs,soybean cheese and nuts),the deletion rate in cases was significantly higher than that in controls(χ²=4.628,p<0.05,OR=4.039; χ²=4.426,P<0.05,OR=7.000; χ²=6.312,P<0.05,OR=5.564;F isher test P=0.031,OR=4.550).GST M1 gene deletion is related to the risk of gastric carcinoma.Environmental factors and GST M1 gene deletion have multiply effect on gastriccar cinoma.