Chitosan is a widely used natural polymer and due to its non-toxic, biocompatibility, absorption, biodegradability and other good properties, it has high application value in the medicine field. Chitosan and its derivatives have been one of the hotspots in medicine research field. This paper reviewed the application of chitosan and its derivatives in the medical materials, antibacterial materials, antitumor, tissue engineering, etc. The biological material with unique performance will attract significant attention in the future and it will be widely used in the fields of cosmetics, food industry, health care products. A chitosan industry with great economic and social benefits will be gradually developed.