Peptide library is a collections of peptides.The peptides display onthe N-terminal of p Ⅲ or p Ⅷ coat protein of bacteriophage through gene cloning.This might be used in the fields associated with molecular recognition,such as: drug design, selection of enzymes inhibitor, vaccines selection, interaction of proteins,etc.Peptide library technique is a lately developed technique with high practical and theoretical value.Peptide library birth,development and potential applications in the future are reviewed.