In order to obtain high purity and specificity polyclonal antibody against soybean globulin， CNBr activated Sepharose-4B was used to purify the antibody which was precipitated by ammonium sulfate. The process of affinity chromatography was time-saving and simple. Purified soy globulin was covalently linked to affinity chromatography packing and the target antibody of the anti-soy globulin was specifically eluted by the nature of antigen antibody specific binding. The non-specific elution peak and the specific elution peak were obtained by affinity chromatography. Through SDS-PAGE identification， the other protein components in the multi antibody serum were washed off by a non-specific method. The concentration of the specific eluted protein was 0.3 mg/mL. The results of indirect ELISA showed that the purified serum was still positive after diluted 128 times. The purified antibody lays the foundation for destroying the structural localization of soybean globulin sensitization sub molecular， thus promoting the research and development of low sensitization food.