Abstract: Carbon dots (CDs) are a novel type of carbon nanomaterials that have attracted numerous attention. CDs possess excellent properties, adjustable luminescence and wide-ranging applications. The classification and different types of structures of CDs were introduced, and the advantages and disadvantages of several main preparation methods of CDs were summarized. The research progress of the application of CDs in the fields of anti-counterfeiting, sensing and light-emitting diodes (LED) was mainly explored and prospected.