Abstract: The optimal extrusion process parameters of wheat bran were investigated by single factor and orthogonal experiment with wheat bran as raw material, the moisture content of wheat bran, barrel end temperature, screw speed and feeding speed as extrusion parameters.The optimal process parameters were as followas:water content 27.5%, screw speed 9 Hz, barrel end temperature 145℃, feeding speed 9 kg/h.Under these parameters, the total dietary fiber and soluble dietary fiber of wheat bran increased by 11.69 and 1.16 percent points.After extrusion, the loose porous structure, uneven surface and increased bare surface area were observed under scanning electron microscopy, which was consistent with its high expansion force and high water holding capacity, indicating that the edible, functional and nutritional properties of extruded wheat bran could be significantly improved.