An electrochemical sensor based on multi-walled carbon nanotubes and poly-L-lysine film modified glassy carbon electrode,on which multi-walled carbon nanotubes were drop-coated and poly-L-lysine film was prepared by electropolymerization,was fabricated.And a novel electrochemical method was established for the determination of lead ion by using anodic stripping voltammetry.Electrochemical behaviors of lead ions on multi-walled carbon nanotubes/poly-L-lysine modified glassy carbon electrode were studied with linear scan voltammetry and cyclic voltammetry techniques.Determination of lead ions was conducted under the optimal experimental conditions such as choices of supporting electrolyte,pH value of the solution,amount of poly-L-lysine,deposition time and deposition potential.Results indicated that a good linear relationship between anodic stripping peak current and concentration of lead ions was observed in the range of 2.0×10-7-8.0×10-5 mol?L-1 with a detection limit of 1.0×10-7 mol?L-1.A recovery experiment on rice sample was conducted by using as prepared modified electrode,and recoveries were in the range of 98%-102%.With good sensitivity and stability,the method was successfully applied in the determination of lead ions in rice sample.