Ribbonfish (Trichiurus haumela) backbone was hydrolyzed by acid protease under the optimal conditions of pH 2.67,45℃,substrate to water ratio of 1:4.38 g/mL,enzyme to substrate of 1/150 g/g protein for 7 h,and then the hydrolysate was separated by ultra filtration of 3 ku to get angiotensin I converting enzyme inhibitory peptide (ACEIP).The ACEIP had ACEIC50 of 0.727 mg/mL.Animal experiments were carried out including single administration and long term administration of spontaneously hypertensive rat (SHR) to determine the anti-hypertensive activity.The results showed that ACEIP from ribbonfish backbone had the anti-hypertensive function,and showed certain dose-effect relationship.The low and high dose treatments reduced the blood pressure of 15 and 20 mmHg of SHR in the long term administration experiment,respectively.