A LC-AFS method was developed for the determination of thimerosal residues in foods of animal origin.The analyte in sample was extracted with the acidic and basic extraction solutions,and separated by liquid chromatography.Thimerosal was mixed with oxidizing reagent and air,then exposed to UV light,and oxidized to inorganic mercury.After hydride generation reaction,the atomized mercury could be determined by atomic fluorescence spectrometry（AFS）.Sample preparation,mobile phase,oxidizing reagent and operating conditions of AFS were optimized.Under the optimal conditions,the calibration curve for thimerosal was linear over the concentration range of 0-20 μg/L with a correlation coefficient of 0.999 4.The detection limit was 0.4 μg/L.The average recoveries of thimerosal from five samples spiked at three levels of 10.0,20.0,40.0 μg/kg were in the range of 71%-83% with RSDs of 1.6%-4.5%.The method was suitable for the determination of thimerosal residues in foods of animal origin.