Abstract: In a supporting electrolyte containing 0.1 mol/L NH₄Ac(pH 7.8), a reduction peak of clozapine(CLP) was found by linear-sweep voltammetry at Hg electrode. The peak shows a potential of -1.34 V(vs. Ag/AgCl) and adsorptive characteristics. When the concentration of CLP is sufficiently low, the sweep rate is sufficiently rapid and the accumulation time is sufficiently long, the peak current is totally contributed by the reduction of the adsorbed CLP. The adsorbed species is most probably neutral molecules of CLP. The saturated adsorption amount of CLP at Hg electrode is 2.7×10^-10 mol/cm² and every CLP molecule occupies 0.62 nm². On the surface of HMDE, the adsorption of CLP obeys Frumkin adsorption isotherm. The adsorption coefficient is 6.28×10⁵, the attractive factor is 0.75. The number of electrons transferred per CLP molecule, n, is 2 and the transfer coefficient of the irreversible adsorptive system of CLP is 0.53. The mechanism of electrochemical reduction of CLP at Hg electrode has been explored. The detection limit of the adsorptive stripping voltammetry of CLP is 8.0×10^-9 mol/L under optimum condition.