Chitin is the most abundant natural amino polysaccharide. It has a similar annual yield as cellulose. Chitin is a kind of highly valuable material in biomedical applications because of its high biocompatibility, biodegradability and non-toxicity as well as its antimicrobial activity and low immunogenicity. It can be easily processed into gels, membrane, nanofibers, beads, nanoparticle, scaffold and sponges, enables its wide applications. In the tissue engineering, it can be used for manufacturing polymer scaffold to satisfy the demands of repairing, replacing, maintaining, or enhancing the function of a particular tissue or organ. In wound dressing, chitin can be used as antimicrobial reagent. In the field of drug delivery, the water-soluble carboxymethyl chitin (CMC) nanoparticle can be used as an effective carrier in drug delivery.