To establish a method for determination of 6 zeranols residues in animal derived foods by liquid chromatography-tandem mass spectrometry with isotope dilution.Methods The sample was added isotope internal standard and extracted using methanol. Methanol was nearly dried-up under nitrogen and the residue was dissolved with ethyl acetate. After solid phase extraction of amino cartridge, the eluent was dried-up by nitrogen at 50 ℃. The analytes were dissolved by the mobile phase and determined by liquid chromatography-tandem mass spectrometry. Results The recoveries of analytes were 84.8%-103.6%, and the relative standard deviations of detection were 3.7%-8.6%. The limits of detection and quantification were 0.03-0.07 μg/kg and 0.10-0.24 μg/kg.Conclusion The method is sensitive, accurate and it can meet the determination requirements of 6 zeranols residues in animal derived foods.