Abstract: A double antibody sandwich ELISA for quantitative analysis of recombinant fusion protein IL-2-HSA was constructed using a polyclonal antibody to human IL-2 for capture and a monoclonal antibody to HSA with HRP-labeled conjugate for detection.The optimal concentration of the first coating antibody and detection antibody were 2 μg/mL and 0.5 μg/mL，respectively.Regression equation of the linear calibration curve was：y=0.442 9 x-1.143 3 with a correlation coefficient of 0.996 6，and the linear detection ranged from 39.06 ng/mL to 1 250 ng/mL.Recovery from the supernatant of fermentation broth was 98.13% to 102.94%.The specificity assay indicated that it had little cross-reactions with IL-2 and HSA.The soundness analysis suggested that fermentation broth，mouse serum and dilution had no influence on the method.The present method can be used in the studies on fermentation，purification and clinical diagnosis.