50.86%。 An experimental method based on controlled mixture ratio of different enzymes in order to improve the emulsifying properties of soybean protein isolate was proposed. The model between the emulsifying properties of partial hydrolysis soybean protein and mixture ratio with aspergillus oryzae proteinase, papain and trypsin was established. The result of enzymes proportion was that aspergillus oryzae protease was 11.79%, papain was 32.93%, trypsin was 55.28%. The optimum hydrolysis condition was obtained by adding 3% of the multiple enzymes/substrate mass ratio to soybean protein isolate by way of dissolving at 9% in water and incubating 3?h. at 40℃ for pH7.5. The emulsifying capacity of hydrolyzing soybean protein with composite enzymes was increased up to 50.86% compared to the control sample.