Abstract: Totally 6 Aflatoxins in feeds were determined by high performance liquid chromatography combined with electrospray ionization triple quadrupole tandem mass spectrometry(HPLC-MS/MS) under the multiple reaction monitoring (MRM) mode, and especially focused on the optimization of extraction, clean-up, HPLC separation and MS/MS parameters of analytes. The Aflatoxins B₁、B₂、G₁、G₂、M_{1 ^and} M₂ were extracted by 84% of acetonitrile aqueous solution, purified by passing through multifunctional cartridges. The elution was evaporated by nitrogen blow and dissolved by mobile phase, and then assayed by HPLC-MS/MS. The limits of detection(LOD) are 0.2 μg•kg^-1, and the limits of quantitation(LOQ) are 0.5 μg•kg^-1. The calibration curves are linear between 0.5 μg•L^-1 and 100 μg•L^-1 for Aflatoxins B₁、B₂、G₁、G₂、M₁ and M₂. Recoveries of those mycotoxins in feeds are 66.1%—108%, and inter-relative standard deviation（n=5） is less than 17.8％ at spiked level of 1.0—100 μg•kg^-1. The method is simple, sensitive and reliable for feed safety.