A poly(carmine) film modified glassy carbon electrode (GCE) was fabricated and the electrochemical behaviors of tinidazole were investigated by electrochemical methods at this modified electrode. A well-defined reduction peak is observed at 0.606V. Compared with that at a bare GCE, the reduction peak potential of tinidazole shifts negatively and the reduction peak current increases significantly at the modified electrode. The influences of some parameters on the reduction of tinidazole were examined and a simple and sensitive electroanalytical method was developed for the determination of tinidazole. The reduction peak current is proportional to the concentration of tinidazole from 1×10 −7 to 5×10 −5 M. The detection limit is about 5.0×10 −8 M for 90s accumulation at a constant potential of 0V. Based on the experimental data a possible mechanism is proposed and discussed. The proposed method was applied to determine tinidazole in drugs and the result was satisfying.