Objective To explore the curative effect of trastuzumab combined with oxaliplatin+S-1(SOX)regimen on patients with advanced gastric cancer(AGC)and its influences on levels of serum tumor markers.Methods A total of 68 pa-tients with AGC were enrolled as the research objects.According to random number table method,they were divided into the con-trol group(34 cases)and the study group(34 cases).The control group was treated with SOX regimen,while the study group was additionally treated with trastuzumab.The curative effect,serum tumor markers[carbohydrate antigen 724(CA724),carcino-embryonic antigen(CEA),carbohydrate antigen 199(CA199)],immunoglobulins(IgA,IgG,IgM)and incidence of drugs toxic-ity were compared between the 2 groups.Results After treatment,total response rate of the study group was higher than that of the control group(67.65%vs 41.18%,P<0.05).After treatment,levels of serum CA724,CEA and CA199 in both groups were decreased,which were lower in the study group than the control group(P<0.05).After treatment,levels of IgA,IgG and IgM in both groups were decreased,which were higher in the study group than the control group(P<0.05).There was no significant difference in the incidence of drugs toxicity between the 2 groups(P>0.05).Conclusion Trastuzumab combined with SOX regimen has significant curative effect on AGC patients,which can effectively reduce levels of serum tumor markers and weaken immunosuppressive function,with high application safety.