Tachykinin peptide isolated and purified from the posterior salivary gland of the mollusk Octopus vulgaris. The tachykinin peptide provides a new approach for developing medicaments and pesticides through studies on the structural activity correlation at the molecular level, is characterized by: (1) number of amino acid residues is 12; (2) N terminal of the peptide is Lys; (3) an amino acid sequence of 5 amino acids from C-terminal is represented by the following amino acid sequence: Phe-Xaa-Gly-Leu-Met (SEQ ID NO: 6), (wherein, Xaa is Val, lie, Phe or Tyr), especially following amino acid sequences are provided: Lys-Pro-Pro-Ser-Ser-Ser-Glu-Phe-Val-Gly-Leu-Met (SEQ ID NO: 1), Lys-Pro-Pro-Ser-Ser-Ser-Glu-Phe-Ile-Gly-Leu-Met (SEQ ID NO: 2).