Abstract: The angiotensin converting enzyme inhibitory peptides ( ACE inhibitory peptides) was designed and synthesized in this research, and the enzymatic hydrolysis of the ACE inhibitory peptides was following studied.In this study, antihypertensive peptides derived from peanut protein were made as templates, and net charge and hydrophobicity which were two important structural parameters were selected to design a series of ACE inhibitory peptides.The ACE inhibitory peptides were hydrolyzed by pepsin and trypsin at 37℃ and were monitored by reversed- phase high performance liquid chromatography ( RP- HPLC) . At last, the relationship between the net charge and hydrophobicity of ACE inhibitory peptides and their enzyme-resistant activity was studied.The results showed that the enzyme-resistant activity of ACE inhibitory peptides was significantly and positively correlated with hydrophobicity of peptides.However, the influence of the net charge to enzyme-resistant activity of ACE inhibitory peptides is not significant.