An analytical method based on high performance liquid chromatography-tandem mass spectrometry was developed for the determination of perchlorate in dairy products.Methods Samples were extracted with 1% acetic acide-acetonitrile solution(1∶2,V/V), and the extract was then cleaned up on an solid-phase extraction(SPE)cartridge and separated on a IC-PakTM Anion HR column(4.6 mm×75 mm,6 μm) by using acetonitrile and ammonium acetate solution(60∶40, V/V) as mobile phase. The analytes were determined by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) with electrospray ionization source in multiple reaction monitoring(MRM). The internal standard calibration was used for quantification. Results Good linearity was observed in the range of 0.1 to 10.0 μg/L. The limit of quantitation of the established method was 1.0 μg/kg in milk and 3.0 μg/kg in milkpowder. The recovery rate of perchlorate was 87.6%-122.0% at three spiked levels in deferent samples, with relative standard deviation of 2.0%-10.0%.Conclusion The method was sensitive, accurate, and suitable for the analysis of perchlorate in dairy products.