Abstract: Dregs of Sacha inchi was used as raw material to prepare peptide. Suitable pretreatment method which could greatly promote protein hydrolysis was screened out. Enzymatic preparation process of Sacha inchi peptide was optimized by response surface methodology,and the relative molecular weight of the gained peptide was analyzed. Results showed that alkaline protease was the most suitable protease for the preparation of Sacha inchi peptide. Pretreatment methods,including sodium sulfite addition of 0.15%~0.45%,surfactant addition of Hexadecyl Trimethyl Ammonium Bromide(CTAB),and ultrasonic treatment with different frequencies,could improve the protein hydrolysis efficiency of Sacha inchi dregs by 10%~50%,among which ultrasonic treatment with 40 Hz was the best. The optimal conditions of Sacha inchi peptide preparation were determined as follows:after 40 Hz ultrasonic treatment of Sacha inchi dregs for 15 min,enzymatic hydrolysis with alkaline protease of 7600 U/g for 6 h at 52℃ was performed,and the hydrolysis degree was as high as 18.21% under these conditions. The peptide obtained by this method was oligopeptide with small and concentrated molecular weight(<1000 Da accounted for 94.64%),in which peptide with the concentrated molecular weight of 180~500 Da accounted for more than half.