Abstract: The experiment had establishmented the extraction method of SIgA in bovine colostrum. The milk of accouchement within one day was centrifuged 10 min by 10000r/min. After dialyzed by 0.2mol/L（PH=6.0）PBS, accommodated the supernatant fluid pH to 6.8-6.9 after disposal of 0.06 mol/L ZnSO4. Then added saturated ammonium sulfate to produce sedimentum, sedimentum dissolved in water. The supernatant fluid were dialyzed by 0.02mol/L（PH=8.0）PBS to no NH4+. Specimen was concentrated, then it was purified by DEAE Sepharose FF chromato bar, gradient elutioned by 02mol/L（PH=8.0）to reach 0.3mol/L（PH=8.0）PBS. Hump proteinum was collected, afterwards it was purified by Sephadex G-200. The elutriant was 0.01mol/L（PH=7.4）PBS. The elutriant appearance hump proteinum was collected, then it was appraised through electrophoresis of SDS-PAGE. The results of the electrophoresis showed that SIgA was metamer. The results of rough determination showed that the content of SIgA was 3.47mg/ml in bovine Colostrum. This experiment had established the method for extract SIgA in bovine colostrum.