Soy protein isolate-dextran conjugate（SDC） was prepared via the Maillard reaction in a liquid system.Then,the covalent binding between dextran and the protein was confirmed using the SDS-polyacrylamide gel electrophoresis technology,and the molecular conformation and functional properties of the product with covalent binding were analyzed by means of circular dichroism spectrography,GPC and DSC.The results show that the product obtained after a 24h reaction in 95% ethanol system at 60℃ possesses better emulsifying activity than that dry-heated for 5d;and that significant structural changes occur in the secondary and the tertiary structures of the conjugate,with the tertiary structure being more compact.Moreover,an improvement of thermal stability of the product is revealed via thermal analysis.