Abstract: Most peptides have high binding affinity and good selectivity for endogenous receptors and are good lead compounds to develop into drugs. Many approved drugs are derived from the structural optimization of peptide molecules, such as the antihypertensive drug captopril and the anti-hepatitis C drug telaprevir. At present, the main problems in the development of peptide drugs include poor stability, short half-life, and high plasma clearance rate; lack of oral availability and poor patient compliance, a complex production process, and high production cost. Therefore, rational modification of peptides can not only reduce the production cost, but also improve the druggability of the peptides. Here we review structural modification strategies for peptides from the perspective of improving their physicochemical properties. These modification strategies are divided into two parts:one is modification of the peptide backbone, including unnatural amino acid modification, pseudopeptide strategy, inverse-peptide strategy, cyclization strategy, and terminal structure modification. Another is modification of the side chains of peptides, including fatty acid conjugation, polyethylene glycol conjugation, protein fusion strategy, and cholesterol conjugation.