Abstract: On the basis of enzymatic hydrolysis and ultrasound-assisted extraction of protein by alkaline solution and acid precipitation, the crude protein from peony seeds was initially separated and extracted. The effects of solid-liquid ratio, ultrasonic temperature, enzyme dosage and ultrasonic time on the extraction rate of peony seed meal protein were investigated by single factor experiments and response surface experiment. The optimal extraction process was determined and its functional characteristics were determined. The optimal extraction conditions of peony seed meal protein by enzymatic hydrolysis and ultrasound-assisted alkaline solubilization and acid precipitation were as follows: Solid-liquid ratio was 1:9.8, ultrasonic temperature was 49.5 ℃, enzyme dosage was 1.9%, and ultrasonic time was 119 min. Under these conditions, the extraction yield of protein reached 90.95%. At this time, compared with the conventional method of protein extraction, the protein obtained had a complete range of amino acids, the content of essential amino acids was improved, and the functional properties such as water holding capacity, oil absorption and emulsification were better than those of the conventional method, and the emulsification stability was better. Therefore, it was speculated that the protein could be used as a food processing emulsifier. Therefore, the peony seed meal protein extracted by enzymatic hydrolysis and ultrasound-assisted alkaline solution and acid precipitation method had higher nutritional value and better functional characteristics.