7S-globulin was purified by using ion-exchange chromatography (DEAE-Sephadex A-50) and affinity chromatography (Con-A Sepharose 4B) from defatted soy flour to study the function of its glycosidic residues. The glycosidic residue was removed by trifluoromethane sulfonic acid treatment without protein denaturation. The properties of deglycosylated derivative were examined and compared with the native one. The heat stability of deglycosylated derivative was decreased and the solbility behavior as a function of pH was changed. The effect of NaCl concentration on solubility was varied. Also the viscosity and digestibility against $\alpha$ -Chymotrypsin was changed.