A polydopamine(PDA) modified glassy carbon electrode(GCE) was fabricated by self-polymerization of dopamine(DA) and was used to detect the trace lead in iodized salt,pure water and tap water.The experiment conditions of self-polymerization of DA and square wave stripping voltammetry were optimized.The optimal conditions were as follows:self-polymerization solution:Tris-HCl(0.01 mol/L,pH 8.5) containing 2 mg/mL DA;self-polymerization time:2.5 h;reaction medium of lead:0.1 mol/L HCl solution;accumulation potential:-1.0 V;accumulation time:300 s. The type of dissolution peak is good and the peak current is high under the optimal conditions.The peak current is proportional to concentration of lead in the ranges of 0.1-1.0 μg/L and 1.0-10.0 μg/L,with a detection limit of 0.016 5 μg/L.The results showed that the new method introduced is simple,sensitive and low cost,and could be applied in the determination of trace lead in iodized salt,pure water and tap water.