Carbon Quantum Dots (CQDs), a class of zero-dimensional carbon nanomaterials with significant fluorescence properties, have become popular in biosensing application research in recent years. Lead comes from many sources in environments such as cosmetics and industrial pollution, and inhalation or ingestion of lead adsorbed on particulate matter can cause lead poisoning, which can cause various diseases, so point of care detection of lead ion (Pb2+) content is extremely important in clinical medical applications. Based on the fluorescence characteristics of carbon quantum dots, a new blue and red dual-emission ratio fluorescent probe was proposed for rapid detection of lead ion content, and the morphological structure and properties of the probe were characterized, detected and analyzed by transmission electron microscope, fluorescence spectroscopy and other means, and the optical properties and application feasibility of Pb2+ response probe were studied in depth. The double emission carbon point is calibrated by comparison with itself to improve the detection effect and sensitivity of the analyte concentration, and effectively avoid the interference of the external environment. This proportional fluorescent uses aqueous synthesis, which is simple and reproducible, and can rapidly respond to Pb2+ in just a few seconds. The detection process can be observed naked-eye from blue to red with only an ultraviolet lamp, which can be used for clinical point-of-care detection. In the concentration range of Pb2+ in line with current medical applications of 0~0.5 mg·L-1, the fluorescence intensity IBCDs/IRCDs has a good linear relationship with concentration, R2=0.987 44, and the detection limit is 0.013 6 mg·L-1. The progressive fluorescence sensing of the probe with Zn2+, Fe3+, K+ and other ten metal interfering ions showed that the probe had a good specific selection for Pb2+. The lead response was measured at different pH environments and incubation times to investigate probe stability.