Abstract: With defatted rice bran as raw material, the extraction of rice bran protein by ultrasonic-assisted was studied. Main factors on extraction yield such as ultrasonic treatment time, ultrasonic power and solid -liquid ratio was investigated through single factor experiments, and the optimum extraction was confirmed through orthogonal experimental design. The optimum rice bran protein extraction conditions were as follows:ultrasonic treatment time 50min, ultrasonic power 380W, and solid -liquid ratio 1 ∶16. Under these conditions, rice bran protein yield reached up to 51.66%.