Peroxyl radical which derived from thermal decomposition of different concentration of 2, 2’-azobis (2-amidinopropane) dihydrochloride (AAPH) was used to oxidize rice protein, and effect of oxidative modification by peroxyl radical on functional properties of rice protein was investigated. The results indicated that rice protein carbonyl content increased as concentration of AAPH increased, which indicated that incubation with AAPH lead to oxidation of rice protein. As the concentrations of AAPH increased, absolute value of zeta potential, solubility, water holding capacity, foaming properties, emulsion properties of rice protein decreased, and oil holding capacity increased. Absolute value of zeta potential of rice protein decreased by 45.70%, solubility decreased by 28.04%, water holding capacity decreased by 58.02%, foaming capacity decreased by 14.61%, foaming stability decreased by 9.66%, emulsion activity decreased by 16.85%, emulsion stability decreased by 9.23%, and oil holding capacity increased by 34.84%. The results indicated that oxidation of rice protein induced by peroxyl radical changed significantly functional properties of rice protein.