Abstract: In order to improve the solubility of rice dreg protein(RDP)and with the bioavailability, rice dreg protein(RDP)and sodium alginate were used as raw materials to synthesize RDP-sodium alginate graft with microwave heating. The ratio of sodium alginate to RDP, microwave temperature, time, power and pH on the modification effect were analyzed. On the basis of single factor experiments, response surface methodology combined with central composite design and variance analysis were employed to optimize process parameters. The optimum conditions of the grafting reaction were as follows:the ratio of sodium alginate to RDP 1.88:1 (w/w), pH10.18, microwave power 186 W, microwave temperature 77.7℃. Based on this condition, the theoretical degree of grafting was 37.03%, which agreed well with the experimental value(36.87%). It turns out that the glycosylation modification technology of rice dreg protein which is gotten by microwave-assisted technology, is not only simple operation, economical and efficient, but also it has an interesting modification effect. The method is worth to extend and use vigorously in the modification of protein.