Abstract: In order to develop antihypertensive substances with safe and non-toxic side effects from food borne, the antihypertensive factors in garlic were selectively extracted by gradual separation and ultrasound-assisted enzymatic hydrolysis. The response surface analysis was adopted to optimize the conditions of pulsed ultrasound-assisted enzymolysis. The results showed that multi-stage isolates of garlic all hah certain inhibitory activity of ACE(Angiotensin converting enzyme), in which direct enzymolysis hydrolysates of garlic power had the best antihypertensive effect. By the response surface analysis, under the conditions of substrate concentration 8 % and the pulsed ultrasound on-time 3 s and off-time 2 s, the optimum parameters of ultrasonic treatment were as following: total treatment time was 72 min, temperature was 45 ?C, pH value was 8.2. Under the optimum conditions, the ACE inhibitory rate of hydrolysates was 67.78%, and the IC50 (half inhibitory concentration) value was 7.57mg/ml. The IC50 value was decreased by 45.03% compared to that using the traditional enzymolysis (without ultrasound treatment), the activity of products from the ultrasound-assisted enzymatic hydrolysis was greatly improved. Garlic ACE inhibitory factor was used for SHR (spontaneously hypertensive rats) test. When the gavage was done for 3 h with the recommended dose of 150 mg/kg, the blood pressure of SHR droped 18.8 mmHg.