The feasibility of using lumbrokinase as a protease in the development of bioactive peptides was investigated, together with the assessment of antihypertensive activity of angiotensin-converting enzyme (ACE)-inhibitory peptides derived from porcine blood proteins and clarification of their underlying mechanisms of action. Lumbrokinase was extracted from earthworms and purified, yielding an enzyme preparation exhibiting an activity of 43 125.87 U•mg–1 protein. The enzyme was used to prepare ACE-inhibitory peptides from porcine blood proteins. After separation and purification, an ACE-inhibitory peptide with an ACE inhibition rate of 91.30% was obtained and designated PBEP-M. An angiotensin (Ang) II-induced human umbilical vein endothelial cell (HUVEC) damage model was established. The toxicity of PBEP-M towards HUVECs was determined using the CCK-8 assay; the secretion levels of endothelin 1 (ET-1), nitric oxide (NO), and reactive oxygen species (ROS) was measured using ELISA kits; and the expression of ACE-Ang II-Ang II receptor type 1 (AT1-R) pathway-related proteins was analyzed using western blotting. PBEP-M significantly promoted cell proliferation at concentrations of 62.5~1 000 μg•mL–1 (P<0.05). At 500 μg•mL–1, PBEP-M significantly increased NO secretion by 84.00% compared with the level in the Ang II group (P<0.05). In addition, PBEP-M significantly reduced the secretion of ET-1 and ROS by 53.66% and 36.94% respectively (P<0.05 vs. Ang II group). Furthermore, PBEP-M significantly reduced the expression of ACE, renin, and AT1-R by 76.76%, 83.96%, and 89.05%, respectively (P<0.05 vs. Ang II group). Moreover, PBEP-M enhanced eNOS expression by 8.77 times (P<0.05 vs. Ang II group). This study provides a theoretical foundation for the application of lumbrokinase as a protease in the development of bioactive peptides and offers new insights for advancing the deep processing of livestock and poultry blood.