Polypeptide drugs have become one of the most crucial tools in drug research and other related fields because of their high pharmacological activity, low dosage, low toxicity and side effects. However, the problems of poor metabolic stability, short half-value period and difficulty in penetration have greatly limit the development of new polypeptide drugs rendering the functional modification of peptides a crucial tool to polypeptide drugs. In this paper, we developed a new strategy for peptide functionalization through the usage of aspartic acid side chain as an endogenous directing group to realize polypeptide’s selective bond arylation.