The invention discloses walnut 
peptide having the 
ACE inhibitory activity and a preparation method thereof. The 
amino acid sequence of the walnut 
peptide is EPNGLLLPGY, and the preparation method of the walnut 
peptide comprises the steps of taking walnut 
pomace as raw materials, selecting appropriate 
protease, preparing walnut antihypertensive peptide coarse products according to the optimal enzymolysis technology, adopting the 
coupling chromatographic technique of the 
membrane technology for conducting fine preparation on the walnut antihypertensive peptide, adopting the 
high performance liquid chromatography for conducting further purification, and adopting the vacuum 
freeze drying or low-temperature 
spray drying technology for preparing final products. According to the walnut peptide, the walnut 
pomace is adopted as the raw materials for developing the 
protein peptide, the raw materials are abundant, the price is low, and the large-scale industrialized production can be satisfied; the walnut peptide has important significance in walnut 
protein product diversification and development and utlization of walnut biological active peptide in functional foodstuff, 
health food or 
medicine.