With the aim to improve the yield of rice bran polysaccharide, the method of extrusion in conjunction with ultrasound was used. On the basis of single factor experimental results, the combination design of quadratic orthogonal rotation was adopted to analyze the conditions of extrusion process and ultrasonic treatment condition, and then the mathematical model of ultrasonic treatment was constructed. The test results show that the rice bran is acquired under the condition of moisture content 20%, extrusion temperature 115℃ and screw speed 120r/min, the yield of rice bran polysaccharide can reach to 7.18% under the optimized conditions of ultrasonic time 21min, ultrasonic power 117W, ultrasonic temperature 72℃ and liquid-solid ratio 8.7mL/g.