Abstract: An electrochemical sensor of Pb2+ was constructed by modifing carbon nanotubes on the glassy carbon electrode.Pb2+ was accumulated at-1.0V in the form of Pb.And then stripped by differential pulse voltammetry at-0.58V.The carbon nanotubes could significantly enhance the detection signal of Pb2+.The amount of carbon nanotubes, pH and supporting electrolyte were optimized.Under the optimized experimental conditions, a linear range of 0.005 to 1μg/mL was obtained with the detection limit of 0.005μg/mL.The linear equation was y=16.0911x-0.2284 (r=0.9962) .The reliability was investigated with satisfactory recovery from 95.4% to 105.5% for real samples.The reproducibility was investigated with a RSD of 1.69% for six measurements.The developed Pb2+ sensor based on carbon nanotubes possesses advantages such as simple fabrication, fast response, low detection limit, good anti-interferential ability and reproducibility.