The enzymolysis technology for soybean protein isolate peptides (SPIP) and preparation technology of soybean protein isolate peptide-Se complex (SPIP-Se) were optimized. The structure properties of SPIP-Se were characterized by absorption spectrum and fluorescence spectrum, and its antioxidation was studied. Results showed that SPIP after enzymatic hydrolysis in temperature 50 ℃, with substrate concentration of 3%, and enzyme-substrate ratio of 5 g/100 g, and chelation at pH 10 in 2 h, for 78 ℃, the selenium binding capacity of SPIP reached 38.143 mg/g. The structural characterization demonstrated that SPIP-Se could cause fluorescence quenching showed higher antioxidant activity than SPIP.