Abstract: A reasonable and reproducible liquid chromatography-mass spectrometry (LC/MS) for detecting β-agonists was developed. The sample was extracted with 5% perchloricacid, centrifuged by a solid-phase extraction procedure with LC-8 cartridges. The products were separated on Agilent Zorbax Eclipse Plus C₁₈ column with a isocratic elution of 0.1%acetate acid and acetonitrile. An electrospray ionization (ESI) source was operated in positive ion mode. The detection limits of five β-agonists are in the range of 0.4-1.2 μg•kg^-1. The experimental results of spiked liver indicate that the average recoveries range from 77.2% to 95.6%.