The invention relates to an active polypeptide prepared by high performance liquid chromatography and application thereof, belonging to the technical field of marine organisms. The new short peptide containing 5 amino acid sequences is separated and purified from the protein enzymolysis product of the Urechis unicinctus viscera, the sequence is identified to be Gln-Pro-Met-Thr-Phe, and the ESI-MS detection molecular weight is 552.72 Da. The in-vitro activity indicates that the active polypeptide has favorable angiotensin converting enzyme (ACE) inhibition activity and can be used for preparing anti-hypertension health food.