Three angiotensin I converting enzyme(ACE) inhibition peptides were isolated from sandworm Sipunculus nudus protein hydrolysate prepared using protamex. Consecutive purification methods, including size exclusion chromatography and reverse-phase high performance liquid chromatography(RP-HPLC), were used to isolate the ACE inhibition peptides. The amino acid sequences of the peptides were identified as Ile-Asn-Asp, Val-Glu-Pro-Gly and Leu-Ala-Asp-Glu-Phe. The IC_(50) values of the purified peptides for ACE inhibition activity were 34.72 μmol L~(-1), 20.55 μmol L~(-1) and 22.77 μmol L~(-1), respectively. These results suggested that S. nudus proteins contain specific peptides that can be released by enzymatic hydrolysis. This study may provide an experimental basis for further systematic research, rational development and clinical utilization of sandworm resources. Consecutive purification methods, including size exclusion chromatography and reverse-phase high performance liquid chromatography (RP-HPLC), were used to isolate the ACE Inhibits peptides. The amino acid sequences of the peptides were identified as Ile-Asn-Asp, Val-Glu-Pro-Gly and Leu-Ala-Asp- Glu- activity were 34.72 μmol L -1, 20.55 μmol L -1 and 22.77 μmol L -1, respectively. These results suggest that S. nudus proteins contain specific peptides that can be released by enzymatic hydrolysis. This study may provide an experimental basis for further systematic research, rational development and clinical utilization of sandworm resources.