A gas chromatography(GC）-negative chemical ionization-mass spectrometric(NCI/MS） method was established for the determination of 7 frequently used pyrethroid insecticides residues in beef.The sample was extracted with acetonitriles and cleaned up with neutral alumina chromatographic column,and then determined by GC-MS under the selected ion monitoring mode(SIM）.Good accuracy,precision and sensitivity were obtained.The calibration curves of 7 pyrethriods were linear between peak areas and concentrations in the range of 10-1 000 μg/L with correlation coefficients(r2） more than 0.997.The recoveries of 7 pyrethriods were in the range of 80%-108% at three spiked concentration levels of 10,20,50 μg/kg,with relative standard deviations(RSDs） less than 12.5%.The limits of detection(LOD） for all pyrethroid ranged from 0.10 μg/kg to 2.5 μg/kg and the limits of quantitation(LOQ） were in the range of 0.50-5.0 μg/kg.