Chitosan is a kind of amino polysaccharide biopolymer with good film-forming, biocompatibility, biodegradability, bacteriostasis and nontoxic, obtained from the deacetylation of chitin, which contains abundant active amino and hydroxyl groups. With creative properties, functions and various applications especially in the biomedical field, chitosan is mainly used as pharmaceutical membrane, gel, microsphere (microcapsule), nanoparticle, drug and gene delivery, etc. This minireview provides an overview on the structure and properties of chitosan, the applications of chitosan biomaterials is introduced, and its research and development in the biomedical field are prospected.