The invention belongs to the technical field of food chemical analysis, and discloses a method for simultaneously detecting three
veterinary drug residues, which comprises the following steps: adding water into a sample, shaking to disperse, then adding an extracting solution, fully oscillating, centrifuging, taking the supernate into a centrifugal tube with a plug, containing a
QuEChERS purification tube (C18, PSA,
anhydrous magnesium sulfate and neutral
alumina powder in a weight ratio of 0.5 g: 0.1 g: 1g: 0.2 g) special for
veterinary drug residues, oscillating, centrifuging, and collecting the supernatant; taking supernate, blowing the supernate in a water bath by using
nitrogen until the supernate is nearly dry or rotationally evaporating the supernate until the supernate is nearly dry, then fixing the volume by using 0.02%
formic acid water containing 0.5 mmol / L
ammonium acetate, adding a proper amount of n-
hexane, fully oscillating and centrifuging, taking a lower-layer solution, enabling the lower-layer solution to pass through a 0.22 mu m nylon membrane, and testing by using a liquid chromatograph-
mass spectrometer. According to the method,
azithromycin,
rifampicin and
acetaminophen in
livestock and
poultry meat can be pretreated at the same time and then detected at the same time, the detection cost is reduced, the detection efficiency is improved, meanwhile, steps are simplified, and personal errors are reduced.