Black soya ACE inhibitory peptide (<3 ku) was prepared， and a hypertensive mouse model was established by using N-nitro-L-arginine methyl ester induction， the mice were divided into control group， hypertensive model group， lisinopril drug group， the BSP low， medium and high dose groups (25， 50， 100 mg/kg) and L-NAME-induced simultaneous gavage BSP high-dose prophylaxis group (L-NAME+BSP). After 4 weeks of continuous gavage， plasma physiological indices were tested and histopathological sections of heart and kidney were observed to investigate the preventive and ameliorative efficacy of BSP and its mechanism of action on hypertensive mice. The middle and high dose groups of BSP had significant antihypertensive effects on hypertensive mice (P＜0.05)， inhibited the rise of ACE， AngⅡ， MCP-1， IL-6 and ET-1 in plasma of mice (P＜0.05)， and significantly increased NO content(P＜0.05)， avoided the disorders of the RAS system of mice， and possessed the efficacy of anti-inflammation and maintenance of the normal function of the vascular cells， and reduced the degree of cardiac damage， fibrosis and renal inflammatory infiltration in mice. Meanwhile， the L-NAME+BSP group delayed the onset of hypertension symptoms in mice， showing a favorable preventive effect. This food-derived black soya ACE inhibitory peptide acts to prevent and ameliorate hypertension in mice by modulating the RAS system.