A simple and sensitive electrochemical sensor was fabricated for the detection of Pb2+ based on L-cysteine（L-Cys）/CdTe quantum dots（QDs） hybrid nanocomposites modified gold electrode（GE）.CdTe QDs were synthesized in aqueous phase.Then,carboxyl labeled CdTe QDs were covalently bonded to L-cysteine on gold electrode,depending on connection between-COOH on MPA-CdTe surface and —NH2 in L-cysteine.The morphology and composition of CdTe QDs and hybrid nanocomposites were characterized by fourier transform infrared spectroscopy（FTIR）,X-ray powder diffraction（XRD）,transmission electron microscopy（TEM）,UV-Vis and fluorescence spectrometry.The electrochemical performance of L-Cys/CdTe nanocomposite and the optimized self-assembly time of CdTe QDs on electrode were investigated by cyclic voltammetry（CV）.The electrochemical behavior of lead ions at L-Cys/CdTe nanocomposite modified gold electrode was investigated by different pulse stripping voltammetry（DPSV）.Under the optimal hybridization conditions,different pulse stripping voltammetric responses of L-Cys/CdTe/GE sensor were in linearity with Pb2+ in the concentration range of 1.0×10-6-1.0×10-2 mol/L with a detection limit of（3σ,n=5） 4.0×10-7 mol/L and a correlation coefficient（r2） of 0.993 8.Therefore,the electrochemical sensor modified with L-Cys/CdTe/GE nanocomposites exhibited the advantages of high sensitivity,good reproducibility and stability,providing a potential platform for the fabrication of other electrochemical sensors.