A highly selective and rapid anodic adsorptive voltammetric method was developed for the （determination） of ultra trace amount of ofloxacin at a carbon paste electrode（CPE）. The ofloxacin adsorbed on the surface of the CPE in a 0.096 mol/L KHP-NaOH buffer solution（pH=5.6） could produce one oxidation peak at 0.92 V（vs.SCE） when scanning was performed from 0.4 to 1.4 V. The relationship between the peak current and the ofloxacin concentration was linear in the ranges of 5.5×10-9～5.5×10-8 mol/L（75 s accumulation） and 3.3×10-8～3.3×10-7 mol/L（30 s accumulation）. The correlation coefficients were 0.996 and 0.998, respectively. Its detection limit was 9.0×10-10 mol/L（S/N=3） for 150 s accumulation. The （electrode） reaction mechanism of ofloxacin was investigated. The proposed method was applied to analyze trace ofloxacin in urine samples. The result was in good agreement with that obtained by spectrophotometry （determination）.
