Abstract: The selenium-rich Moringa oleifera leaves protein was extracted from the selenium-rich Moringa oleifera leaves. The preparation of angiotensin-converting enzyme (ACE) inhibitory peptides from selenium-rich Moringa oleifera leaves was optimized by single factor experiments and response surface method. The ACE inhibitory activity, amino acid composition and selenium content of the optimal enzymatic hydrolysate were analyzed and characterized. The results showed that the optimal hydrolysis conditions of ACE inhibitory peptides were as follows: time 3 h, pH7.5, enzyme to substrate ratio 0.23%, substrate concentration 5.97% and temperature 39.2 ℃. The ACE inhibitory peptides prepared under these conditions showed strong ACE inhibitory activity (IC₅₀=0.522 mg/mL), rich in essential amino acids (24.05%) and hydrophobic amino acids (20.6%), and the selenium content was 1.86 times that of the raw material of Moringa oleifolia leaves. The ACE inhibitory peptides of selenium-rich Moringa oleifolia leaves protein had dual characteristics of functional factor and natural food. This study could provide theoretical basis for the development of antihypertensive drugs and related functional foods.