Transferrin receptor(CD71 or TFRC)is an attractive target for cancer therapy.However,high level of endogenic transferrin(TF)leads to competitive binding that increases the dose of therapy agents with side effects.To solve this problem,phage display has been used in this study to select CD71-specific peptides which will provide the candidate to replace the TF for cell imaging and drug delivery.After four rounds of biopanning,the specific phage library was enriched with the increasingly strict screening condition.Then twenty phage clones were chosen for binding characterization by ELISA and all the positive phage clones were send to sequencing.After sequence analysis,six peptides were identified that specifically bind to the CD71.The peptide Y1 was chosen for further characterization.The peptide Y1 is bound to CD71 with high binding affinity.More importantly,peptide Y1 did not compete with the either of TF or CD71 antibody,which demonstrated that the peptide Y1 bind to different site on CD71.Interestingly,the peptide Y1 can enter into the HeLa cells which express high level of CD71.All these studies indicated that these peptides have great potential in cancer diagnosis or drug delivery.