Abstract:. This study aimed to identify angiotensin-converting enzyme (ACE)-inhibitory peptides derived from fish swim bladder collagen a. Grass carp swim bladder collagen was subjected to sequential enzymatic hydrolysis using a protease blend, pepsin, and trypsin to prepare a swim bladder collagen hydrolysate (SCH). Peptides in SCH were identified by liquid chromatography–tandem mass spectrometry (LC-MS/MS), followed by in silico screening and in vitro ACE inhibition assays to identify and validate bioactive peptides. Network pharmacology was further employed to predict targets and pathways potentially associated with their antihypertensive effects. A total of 367 peptides were identified in SCH, and four potential ACE-inhibitory peptides were selected through in silico screening. In vitro validation showed that FPTPVP exhibited the strongest ACE-inhibitory activity among the selected peptides, with a half-maximal inhibitory concentration (IC??) of 0.62 mmol/L. Network pharmacology predictions suggested that the potential antihypertensive effects of FPTPVP may involve targets such as ACE, MMP2, MMP9, and STAT3, as well as biological processes and pathways associated with the renin–angiotensin system, inflammatory responses, extracellular matrix remodeling, and vascular function regulation. This study identified FPTPVP from sequentially hydrolyzed grass carp swim bladder collagen and confirmed its in vitro ACE-inhibitory activity, providing experimental evidence and mechanistic clues for further investigation of its potential antihypertensive effects. These findings also support the valorization of fish swim bladder by-products.