To find anti-hypertensive lead drug, angiotensin converting enzyme (ACE) inhibitory peptides were synthesized and their effects on inhibiting ACE activity were investigated. ACE inhibitory peptides were synthesized via Fmoc solid-phase synthesis, isolated and purified through reversed phase high-performance liquid chromatography (RP-HPLC), and identified by mass spectrometry. A RP-HPLC analysis method was used to test ACE inhibitory activity in vitro of these ACE inhibitory peptides. Six octapeptides were successfully synthesized, and the analytical results of mass spectrum were consistent with their theoretically calculated data. Among these synthetic octapeptides, the anti-SARS (severe acute respiratory syndromes) octapeptide had the most obvious ACE inhibitory activity with an IC50 value of 3.4 x 10(-5) mol x L(-1). So octapeptide AVLQSGFR-OH (anti-SARS peptide) was found to be the strongest candidate for potential development as an anti-hypertensive drug and had the implication of further study.