Glycinin is an important food allergen. In this study we aimed to develop a safe and effective method to reduce the antigenicity of glycinin. Glycyrrhiza uralensis polysaccharide (GUP) was extracted and purified. As a glycosyl donor in Maillard reaction, GUP was conjugated to glycinin with reaction conditions optimized based on amino acid binding rate and inhibition of glycinin antigenicity. The results showed that optimal reaction conditions included a ratio of 1:3 for GUP to glycinin, temperature at 55ºC, reaction time of 72 h, humidity of 72% and final concentration of mixed solution of 11%. The inhibition rate of glycinin antigenicity and the rates of allergic diarrhoea and mortality in mice were all the lowest for GUP-glycinin conjugates synthesized under these reaction conditions. The structure of GUP-glycinin conjugates was characterized by UV spectrum, FT-IRand SDS-PAGE analysis. In conclusion, using GUP as a sugar moieties donor for Maillard reaction is an effective method to reduce the antigenicity of glycinin.