Abstract: Collagen peptides, renowned for their excellent biocompatibility, bioactivity, and facile absorption by human body, have been extensively developed and utilized in the food, biomedical, and cosmetic industries. This review focuses on recent development in the preparation methods, bioactivities, and applications of collagen peptides. Firstly, an overview of the current preparation methods and principles of collagen peptides is provided, followed by a comparison of the advantages and limitations of different methods. Subsequently, a summary of the bioactivities exhibited by collagen peptides is presented, including the antioxidant activity, antimicrobial activity, antifreeze activity, angiotensin-converting enzyme (ACE) and inhibition of dipeptidyl peptidase-IV (DPP-IV). Finally, the application of collagen peptides in food additives and functional foods, based on the bioactivity has been discussed. Additionally, the latest applications of collagen peptides in the fields of medicine and cosmetics have also been introduced.