A method was developed for the determination of zoalene and its metabolite(3-amino-5-nitro-o-toluamide,3-ANOT) in chicken muscle by dispersive solid phase extraction and liquid chromatography tandem mass spectrometry(LC-MS/MS).The samples were extracted with acetonitrile and purified by dispersive solid phase extraction method.After diluted with 0.1% formic acid,the extract was filtered through 0.22 μm filter and 10 μL of the filtrate was injected into LC for analysis.The target compounds were separated on an Acquity BEH C18 column with acetonitrile-0.1%formic acid as mobile phase with gradient elution,and detected by MS under multiple reaction monitoring(MRM) with positive and negative ionization switching mode.The analytes were quantified by the external standard .Good linearities were obtained for zoalene and 3-ANOT at the concentration of 1-500 μg?L-1,with correlation coefficients of 0.999 5 and 0.999 4,respectively.The recoveries of zoalene and 3-ANOT in chicken muscle at fortified levels of 50-4 500 μg?kg-1 were between 81% and 94%.The intra-assay RSDs were in the range of 2.1%-5.3% and the inter-assay RSDs were 4.3%-6.2%.The limits of detection of zoalene and 3-ANOT were 10 and 14 μg?kg-1,respectively,and their limits of quantitation were both 50 μg?kg-1.The results indicated that the method could meet the requirement for simultaneous determination of zoalene and 3-ANOT in chicken muscle.