The invention discloses a PD-1 targeted polypeptide and an application thereof. The invention further discloses a preparation method for polypeptides and pharmaceutical compositions containing the polypeptides. The polypeptide disclosed by the invention can be bonded to a human PD-1 protein, so that the polypeptide can serve as a leader peptide for developing human PD-1 receptor inhibitors, and a foundation is provided for the development of antitumor drugs. The polypeptide disclosed by the invention can be prepared by adopting a chemical synthesis method and has the advantages of high purity, small molecular weight, safety, reliability and the like.