Collagen, the most widely distributed protein in the human body, has become a crucial biomaterial in tissue engineering due to its biodegradability, biocompatibility, and versatility. This review provides an overview of collagen-based biomaterials, highlighting their applications in regenerative medicine. Collagen is extracted from various sources, including animal tissues and recombinant sources, and can be processed through decellularization or polymerization to form functional scaffolds. Cross-linking techniques, such as physical, chemical, and enzymatic methods, are essential for enhancing the mechanical and enzymatic resistance of collagen-based biomaterials. Sterilization methods, including low-dose gamma irradiation and ethylene oxide sterilization, are crucial to ensure the safety and efficacy of these materials. Recent advances in collagen-based biomaterials include their use in osteochondral defects, vascular diseases, skin and cornea regeneration, urogenital system disorders, neural migration, dermal fillers, wound dressings, and delivery systems. These materials have shown promising results in both fundamental research and clinical applications, making collagen a valuable resource for tissue engineering and regenerative medicine.Collagen, the most widely distributed protein in the human body, has become a crucial biomaterial in tissue engineering due to its biodegradability, biocompatibility, and versatility. This review provides an overview of collagen-based biomaterials, highlighting their applications in regenerative medicine. Collagen is extracted from various sources, including animal tissues and recombinant sources, and can be processed through decellularization or polymerization to form functional scaffolds. Cross-linking techniques, such as physical, chemical, and enzymatic methods, are essential for enhancing the mechanical and enzymatic resistance of collagen-based biomaterials. Sterilization methods, including low-dose gamma irradiation and ethylene oxide sterilization, are crucial to ensure the safety and efficacy of these materials. Recent advances in collagen-based biomaterials include their use in osteochondral defects, vascular diseases, skin and cornea regeneration, urogenital system disorders, neural migration, dermal fillers, wound dressings, and delivery systems. These materials have shown promising results in both fundamental research and clinical applications, making collagen a valuable resource for tissue engineering and regenerative medicine.