Abstract: In order to get a new type of hypoglycemic peptide,ultrasonic- assisted enzymatic was used to prepare peony seed hypoglycemic peptide,and the process was optimized by one- factor and response surface experiments.Five factors were determined to be optimized by the response surface methodology from the seven factors of enzymolysis. The optimal process parameters were temperature of 37.3 ℃,time of 21.68 min,power of60.52 W( volume of 600 cm3),p H8.01,enzyme of 10202 U/g,protein concentration of 2%,frequency of 28 k Hz,and the actual inhibition rate was 40.25% under this condition,which was increased by 14.9% compared with the no ultrasonic condition. This study not only provided basis for ultrasonic assisted preparation of peony seeds hypoglycemic peptide,but also gave a new utilization direction of peony seed protein.