In order to optimize the ultrasonic wave extraction technique of polysaccharides from Auricularia auricula, the technique conditions were carried out by response surface methodology. Then the molecular weight distribution of AAP extracted were studied. Two factors, ultrasonic wave and extraction time in water were screened from six factors . The singal-order tests and integrated curvature detection of the two factors were carried out. After that, the experiment domain approached to the optimum point, the optimum technology conditions of ultrasonic wave extraction of AAP were determined by central composite design: ultrasonic wave power 908W, extraction time 100°C, and the AAP yield of ultrasonic wave extraction approached to 24%. It was indicated that ultrasonic wave can promote the yield of the large molecular weight components by the analysis of molecular weight distribution.