Conventional　tumor　therapeutic　modalities,　such　as　radiotherapy,　chemotherapy,　and　surgery,　involve　low　tumor　inhibition　efficiency,　non-targeted　drug　delivery,　and　side　effects.　The　development　of　novel　and　practical　nano-drug　delivery　systems　(DDSs)　for　targeted　tumor　therapy　has　become　particularly　important.　Among　various　bioactive　nanoparticles,　chitosan　is　considered　a　suitable　candidate　for　drug　delivery　due　to　its　non-　toxicity,　good　biocompatibility,　and　biodegradability.　The　amino　and　hydroxyl　groups　of　chitosan　endow　it　with　the　diverse　function　of　chemical　modification,　thereby　improving　its　physical　and　biological　properties　to　meet　the　requirements　of　advanced　biomedical　applications.　Therefore,　it　is　necessary　to　review　the　property　and　applications　of　chitosan-based　materials　in　biomedicine.　In　this　review,　the　characteristics　of　chitosan　related　to　its　applications　are　first　introduced,　and　then　the　preparation　and　modification　of　chitosan-based　nanoparticles,　including　the　function　tailoring　of　chitosan-modified　nanoparticles,　are　demonstrated　and　discussed.　Finally,　the　opportunities　and　challenges　of　chitosan-based　nanomaterials　in　this　emerging　field　are　proposed　from　the　perspective　of　the　rational　and　systematic　design　for　the　biomedicine　field.