Carbon　dots　(CDs)　is　a　kind　of　carbon　nanoparticles　with　a　plentiful　of　surface　functional　groups　and　tunable　emission　with　different　excitation　wavelength.　Broadly　speaking,　CDs　include　carbon　nanodots,　carbon　quantum　dots,　graphene　quantum　dots,　carbonized　polymer　dots.　Due　to　the　unique　nature,　they　are　explored　for　various　applications　in　the　bio-related　fields　such　as　bioimaging,　sensor　for　ion　and　(bio)molecules,　catalyst,　LED　and　other　fields.　They　are　viewed　as　great　alternative　tracers　to　the　current　fluorescent　biomarkers　in　personalized　nanomedicine　and　surgery　operation　monitoring.　In　this　review,　we　summarized　the　recent　progress　in　the　development　of　CDs,　including　improvement　in　fluorescence　properties,　two-photon　fluorescence,　and　integration　with　other　modalities　as　theragnostic　agents.　Specifically,　we　discussed　the　preparation　of　dual-modal　imaging　agents　to　improve　the　accuracy　of　diagnosis,　the　combination　of　imaging　and　targeting　functionality　for　the　effective　accumulation　of　biomarkers,　and　the　integration　of　imaging　and　therapeutic　agents　to　effectively　monitor　the　localization　and　concentration　of　therapeutic　agents.　Finally,　the　theragnostic　agents　composed　of　three　functionalities　(e.g.　targeting,　imaging,　and　therapy)　were　summarized　to　provide　readers　with　future　perspectives　in　this　field.