Abstract: Rice bran is the main by-product of the rice milling process with high protein content. Although there is a large amount of rice bran in China, most of it is used to raise animals. Therefore, for the economic benefits of the rice processing industry, it is inevitable to fully develop the added value of rice bran. Longjing No.31 rice bran was chosen as the protein source in order to study the effect of extrusion stabilization treatment on the protein structure and functional properties of each component of rice bran, , and effects of rice bran extrusion stabilization using twin-screw extruder on structural and functional properties of rice bran protein fractions were also investigated. The results showed that the solubility, foamability and oil-holding capacity of each component protein of rice bran were significantly reduced after extrusion treatment (P<0.05), this is because insoluble aggregates are formed after high temperature, high pressure and high shear. The water-holding capacity, foaming stability and emulsion stability were increased, among which the water holding capacity of gluten increased the most, 39% higher than that before extrusion. After extrusion, the structure of gluten changed, forming more random coil structures, and the unfolded protein molecules interacted with each other to form a more stable network structure, thereby increasing the foaming stability of gluten. As well as, its emulsifying activity was significantly different from that of other protein fractions. On the other hand, the albumin and globulin contents decreased by about 5% and 10%, while gluten increased by about 8% after extrusion, respectively. The emulsifying ability of rice bran protein was related to factors such as solubility, and the thermal denaturation caused by stabilization reduced the emulsifying ability of each component of rice bran. Structural analysis indicated that changes in protein fractions after extrusion mainly attributed to a recombination among them, which indicated by differences in the secondary structure. The α-helix, β-turn, and random coil contents of the albumin decreased significantly after extrusion, while the content of β-sheet folding increased significantly. Moreover, the rice bran gluten showed a different trend from that of albumin, and the secondary structure of gluten changed significantly in the amide I zone, the content of α-helix, β-turn and random coil increased, and the content of β-sheet decreased. After high temperature and high pressure treatment, the hydrogen bond of the protein was broken, so the protein was partially denatured and its structure was also changed. The results can help in understanding changes occur in structural and functional properties of rice bran protein fractions during extrusion to promote the utilization of rice bran protein in the food industry.