In this paper, the antihypertension effect of rice peptide (RP) was studied. With spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) as the research objects, RP disposable gastric and long-term gastric irrigation experiments were carried out and systolic blood pressure (SBP) was measured. At the end of the long-term gastric irrigation experiment, the content of nitric oxide (NO), angiotensin-converting enzyme (ACE), angiotensin II (Ang II) and renin in the plasma and the activity of ACE were determined. The results showed that RP could reduce systolic pressure of SHR and had time-dose dependence while high-dose RP significantly reduced systolic pressure by 24.6 and 17.2 mmHg, respectively after a single and long-term gastric irrigation test. RP also could inhibit the activity of ACE and increase the release of NO. These results suggested that the decompression mechanism of RP is likely to be related to the regulation of the renin-angiotensin system (RAS) and NO.