The invention discloses anti-opioid peptide, and antagonistic peptide and application thereof. The anti-opioid peptide has one of the following amino acid residue sequences: 1) SEQ ID NO:1 in a sequence table; and 2) the amino acid residue sequence shown as the SEQ ID NO:1 in the sequence table is replaced and deleted by 1 to 10 amino acid residues or added with polypeptide with the effect of resisting morphine damages. The antagonistic peptide has one of the following amino acid residue sequences: 1) SEQ ID NO:5-7 in a sequence table; and 2) the amino acid residue sequence shown as the SEQ ID NO:5-7 in the sequence table is replaced and deleted by 1 to 10 amino acid residues or added with polypeptide with the effects of enhancing morphine analgesia, reversing morphine tolerance and/or weakening or eliminating abstinence syndromes. The anti-opioid peptide and an active segment and the antagonistic peptide thereof exert an important effect in the field of preparation of medicinal and drug treatment medicaments and have wide application prospects.