Objective To study the relativity of S/CO qualitative determination of hepatitis B surface antibody and quantitative assay.Methods The different concentrations of sera were determined with time-resolved fluorescence immunoassay and enzyme-linked immunosorbent assay. The standard curve was drawn and the equation was established.Results In the curve, S/CO level was positively correlative to the quantitative detection value, and the conversion equation was Y=8.911 8×e0.177 4X.The intraclass correlation coefficient of S/CO calculating level and quantitative value was 0.934.Conclusion The content of hepatitis B surface antibody can be estimated by S/CO value. It can be used in basic-level laboratories which don′t undertake the quantitative determination of HBV markers.