Abstract: Effect of ultrasound pretreatment and glycosylation reaction on the structure and emulsibility properties of bovine serum albumin ( BSA) were investigated by ultraviolet spectroscopy and fluorescence spectroscopy. After ultrasound pretreatment, the surface hydrophobicity of BSA increased and the intrinsic fluorescence intensity of BSA increased, but the samples with ultrasound pre-treatment and glycosylation reaction, the intrinsic fluorescence intensity of BSA reduced, surface hydrophobicity decreased, and emulsibility properties increased. It indicated that the ultrasound treatment combined with the glycosylation reaction changed the tertiary structure of BSA, which promoted the degree of glycosylation reaction and improved the emulsifying performance of the primary product.These results indicated that ultrasound can provide a promoting method for glycosylation in food processing.