Abstract: Phage display peptide library technology facilitates displaying peptides of high diversity on the surface of phage coat proteins, which with their independent space structure bind with ligands to screen the specific molecule epitopes.With the development of this technology, it becomes an effective and powerful tool in tumor research.As nuclide carrier, peptides screened from phage display library binding specifically with tumor cells and tumor blood vessels, can be manufactured into a probe for prophase diagnosis of tumor, localization of metastasis and nuclide therapy.Targeting chemotherapy drugs on the basis of peptides greatly lower the risk of killing normal tissue and organs, which impulses entering a new therapy time.