Abstract: In order to improve the emulsifying properties of SPI- DX complexes prepared by water bath and microwave methods.The graft degree of the composites and browning degree were determined by OPA and UV spectrophotometer at 420 nm,then the functional properties and secondary structure of the conjugates prepared in two ways were compared. The results showed that microwave method can make more dextran have Maillard reaction with SPI while reducing the complex's browning degree. The SPI- DX conjugates obtained from the two methods were improved in solubility,emulsification,the effect to solubility in traditional water bath method was better than microwave method,and the emulsifying property of water bath method also higher than that of microwave way. Fourier transform infrared spectroscopy showed that the two conjugates ' content of α- helix,β- turn and random coil were decreased,but the content of β- sheet was increased.