Abstract: Objective：To establish an antibody-sandwich ELISA method for detection serum glypican 3 (GPC3). Methods：The monoclonal and polyclonal antibody to GPC3 were prepared by ourselves, and a doubleantibody-sandwich ELISA method for the detection of serum GPC3 was established. Results：The linearity was from 0.2 to 12.5 μg/L. The lowest limit was 0.101 μg/L. The coefficients of variation (CV) of withinrun and betweenrun were less than 5.99％ and 6.96% respectively, and the average recovery was 99.9%. Clinical studies showed that the concentration of GPC3 in the sera of patients with primary hepatocarcinoma was 5.43(2.288.62) μg/L, which was significantly higher than that in benign liver diseases (P<0.05). When cut-off value was 3.19 μg/L, the sensitivity and specificity of primary hepatocarcinoma diagnosis was 85.4% and 98.9% respectively. Conclusion：The established ELISA is sensitive, specific and accurate in this study. The detection of serum GPC3 should be helpful for the diagnosis of primary hepatocarcinoma.