Abstract: To explore the Nelumbo nucifera Gaerta protein hydrolysis characteristics and received antihypertensive activity polypeptide by papain, Nelumbo nucifera Gaerta as the raw material, angiotensin converting enzyme (ACE) inhibition rate and hydrolysis degree (DH) were used as a measure indicator and treated by papain to obtain hypotensive activity peptides. By orthogonal test L₁₂ (3⁴ ) factors that determined the papain hydrolysis of Nelumbo nucifera Gaerta which optimal combination was:pH value 6.0, hydrolysis temperature 55℃, substrate concentration 5% , enzyme concentration of 8% . By the value of R, the relationship between primary and secondary of factors was temperature>pH>substrate concentration>enzyme concentration . Research of hypotensive activity polypeptides in different hydrolysis degree, the results showed that ACE inhibition rate and hydrolysis degree in a linear relationship. Macroporous adsorption resin was uesd for polypeptide to determinat hypotensive activity showed that after 25% ethanol, the resulting polypeptides hypotensive activity highest 55.78%, and the IC 50 was 0.045mg/mL.