Enamel demineralization of the brackets caused by surrounding bacteria is the main challenge facing orthodontists. Aiming to resolve this issue, here we originally reported a novel antibacterial coating based on ZnO and carbon quantum dots (CQDs) composite prepared via a facile and environmentally-friendly method. As desired, the bracket modified with ZnO/CQDs coating exhibited excellent antibacterial performance than the unmodified bracket (Streptococcus mutans 96.13%, Staphylococcus aureus 90.28% and Escherichia coli 92.35%) under natural light. In addition, the natural light antibacterial mechanism was explored, which could be ascribed to the upconversion fluorescence of the CQDs and the interaction between CQDs and ZnO. (C) 2018 Published by Elsevier B.V.