Abstract: Three monoclonal antibodies （McAbs）: Gs-2, Ps-7 and Ps-10 were used to detect cancer associated antigen in gastric juice in patients with gastric cancer by biding inhibition SABC-ELISA method compared with antigen expres-sion in gastric cancer tissue simultanously. the mean inhibition rate are significantly higher in patients with gastric cancer than that of benign lesions or normal control （P＜0.001）. the postive rates of gastric cancer were 71.4%＞ 65.0%, 74.6% respectively. combination of three McAbs （cocktail） showed a higher positive rate in gastric cancer （92.0%）, whereas in "control" group, it remained low （12.0%）. the resnlts provide a useful tool in the diagnosis of gastric cancer.