Abstract: The aim of this work was to enhance of the protein extraction yield of Auricularia auricula by ultrasonic-enzymatic method and its functional properties under different pH ​were studied. Through single factor experiments, combined with Plackett-Burman experiment design and Box-Behnken experiment design, the optimum extraction process for the ultrasonic-enzymatic method of Auricularia auricula protein was determined, and the functional properties of the protein were measured under different pH. The results showed that the optimum extraction process parameters of Auricularia auricula protein were as follows: Solid-to-liquid ratio 1:88 (g/mL), ultrasonic time 30.5 min, enzymolysis pH8.5, enzymolysis temperature 65.8 ℃, under these conditions, the protein extraction rate was 57.11%±0.12%. The pH had significant effects on the functional properties of Auricularia auricula protein. The protein foam stability was the best at pH3.5, reached 74.90%. With the increasing of pH (3.5~9.5), solubility, foaming, emulsifying, emulsifying stability, water holding capacity and oil absorption increased significantly (P<0.05), and foam stability decreased significantly (P<0.05). The results would provide a theoretical basis for the extraction, utilization and comprehensive development of Auricularia auricular protein.