Reasonable, effective and rapid food safety detection methods are of great significance for ensuring food safety. As a new fluorescent carbon based nanomaterial, carbon quantum dots (CQDs) exhibit the advantages of large Stokes shift, good photostability, adjustable emission wavelength and photochemical stability. In addition, CQDs have excellent biocompatibility, and their chemically modified surface can be coupled with antibodies, nucleic acids and other macromolecules without changing their biological properties. The use of CQDs fluorescence detection technology can improve the sensitivity, shorten the detection time, reduce the detection limit, and save human and material resources. Therefore, CQDs can be considered to be one of the most powerful carbon nanomaterials in sensor research. In this paper, the structure, classification and fluorescence mechanism of carbon dots are reviewed, with emphasis on recent progress in green synthesis based on CQDs and the application of CQDs as fluorescent probes in food safety detection, in order to provide new ideas for the synthesis of CQDs and the development of rapid food safety detection technologies.