An effective method of high-performance liquid chromatography（HPLC）was developed for the determination of imidazole，the harmful ingredient in cigarette additives based on pre-column derivatization with dansyl chloride（Dns-Cl）.The additive samples firstly underwent the treatment of a buffer of carbonate solution，followed by the pre-column derivatization with dansyl chloride，then the extraction with ethyl acetate，dryness，evaporation，dilution with acetonitrile and filteration，separation on a C18 column，elution with acetonitrile-water by gradient elation，and finally the detection with a fluorescence detector.The optimum derivatising conditions of imidazole with dansyl chloride are as follows:concentration of dansyl chloride:1 000 mg/L;temperature of reaction:45 ℃;pH of buffer solution:10.0;time of reaction:40 min. The imidazole derivative was quantified by the external standard method.There was a good linearity for the analyte in the range of 0.5-500 mg/L with a correlation coefficient of 0.999 5.The limits of detection of the method for imidazole derivative was 0.24 mg/kg，and the limits of quantitation was 0.80 mg/kg.The recoveries at three spiked levels ranged from 89.1% to 97.2% with RSDs not more than 7.5%.Results showed that the method was accurate and reliable，and was applicable to the determination of imidazole content in cigarette additives.