Cyclopeptide classifications have been performed systematically in present review, where the synthetic methodologies of the most representative cyclopeptides in documents, such as classical cyclopeptides and atypical cyclopeptides like DKPs (diketopiperazines), Freidingers and some loop chains containing ether, alkene, single or poly sulphur ether, rigid bridge, amine, Mannich base, biphenyl, etc., were described respectively.

Key words: structure modification of peptide, cyclopeptide classification, cyclopeptide synthesis