Carbon　dots　(CDs),　a　new　class　of　fluorescent　materials,　have　recently　attracted　considerable　research　interest.　CDs　have　overcome　some　defects　of　traditional　nanomaterial.　In　addition　to　their　small　size　and　optical　properties,　CDs　have　the　excellent　advantages　of　good　biocompatibility　and　are　easy　to　achieve　surface　functionalization.　Since　this　discovery,　CDs　can　be　widely　used　in　the　field　of　biochemical　sensing　and　environmental　testing.　This　article　reviews　the　progress　in　the　research　and　development　of　CDs　on　their　syntheses,　applications　for　the　fluorescence　detection　and　possible　mechanisms.　Finally,　we　have　an　outlook　of　the　research　trends　and　future　prospects　of　CDs.