In recent years, collagen peptides (CP) have become a research hotspot in delaying chronological skin aging. Animal experiments have shown that CP can repair chronologically aged animal skin by promoting collagen synthesis, inhibiting collagen degradation, and increasing antioxidant enzyme activity. Cell experiments showed that CP can promote proliferation of fibroblasts and synthesis of collagen and elastin by stimulating nuclear factor-κB signaling pathway and transforming growth factor-β/drosophila mothers against decapentaplegic signaling pathway. Clinical studies have demonstrated that long-term oral supplement with CP or CP in combination with other antioxidant active substances can increase the skin moisture content and reduce transepidermal water loss, improve skin wrinkles and elasticity, as well as improve the skin collagen fiber structure, dermal and epidermal quality and the overall condition of facial skin. This review summarizes recent studies on mechanisms underlying chronological skin aging and mechanisms of action of CP in repairing chronologically aged skin, in order to provide a theoretical basis for further clinical research into and application of CP in repairing chronologically aged skin.