Abstract: In order to explore the effect of protein 11S/7S ratio(0.55~5.09)in soybean on the emulsion properties of soymilk,7 soybean varieties with different 11S/7S ratio were selected to prepare soymilk. Protein solubility,particle size,zeta potential,soymilk viscosity,free sulfhydryl,surface hydrophobicity and precipitation rate in soymilk was detected respectively,which were closely related to the emulsion properties of soymilk. The results showed when the ratio of 11S/7S in soybean was low,the particle size and the viscosity of soymilk was low,the protein solubility,zeta potential absolute value,the free sulfhydryl contents,the surface hydrophobicity was separately high,which lead the low precipitation rate and high stability of soymilk. On the contrary,when the 11S/7S ratio in soybean was high,the particle size and the viscosity of soymilk was large,the protein solubility,zeta potential absolute value,the free sulfhydryl contents,the surface hydrophobicity of soymilk was low respectively,which induced the high precipitation rate and low stability of soymilk. However,when the ratio of 11S/7S in soybean was 3.0~3.49,there was no significant difference in the above indexes of soymilk(P>0.05).