Carbon quantum dots (CQDs) have been synthesized by a rapid and simple approach, easy to perform and environmentally friendly. CQDs nanoparticles synthesized from natural biomass raw materials such as kumquat and scallion are processed with the supporting of microwave. In addition, the synthezised CQDs nanoparticles were analyzed to determine the composition, structure and optical properties by UV-vis, FTIR, XRD, TEM and EDS. Results showed that the CQDs with average particle size ~4–5 nm was synthesized at microwave power of 900 W for 10 min. The chemical composition of CQDs determined by Energy-dispersive Xray spectroscopy (EDX) including C (47.80%); O (32.69%); N (18.85%) and other elements. Moreover, the synthesized CQDs have been oriented in the detection of metal ions (Fe3+) at a low concentration of 250 M and ionic strength reached limits of detection in the range from 0 to 1 mM. Therefore, CQDs is potential and promise nanomaterial with highly chemical sensitivity to apply in many fields such as chemical sensors, biological sensors, catalysts, biomedicals, optoelectronics, etc. in the current time and future.