Abstract: Objective To develop an efficient and accurate method for simultaneous determination of multi-residues of 9 β-agonists in meat and liver by using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and to investigate the residues in porcine, bovine, and ovine muscles and livers collected from local markets in Shenzhen. Methods Samples (10.0 g) were hydrolyzed by β-glucuronidase /sulfatase at 37 ℃ overnight to free bound β-agonists, extracted by perchloric acid, purified by HLB and MCX cartridges, and reconstituted with a methanol-0.1% formic acid (10+90).The residues of β-agonists were determined by electrospray ionization-trandem mass spectrometry, and quantified by internal standard method by d6-ractopamine, d9-clenbuterol and d3-salbutarnol. Results The linear relationships of the nine target β-agonists were optimal in the range of 0-50 μg/L and the linear correlation coefficient was >0.995. The limits of quantification were 0.5 μg/kg for 9 β-agonists in porcine, bovine, and ovine muscles and livers. Average recoveries were 66.2%-119.4% with relative standard deviations of 0.36%-10.02%. Nine of 720 samples detected by this method were positive, with a detection rate of 1.25%, of which the detection rates were 0.56% (4/720) for ractopamine, 0.42% (3/720) for clenbuterol, and 0.28% (2/720) for phenylethanolamine A. Conclusion This method proved to be quick and accurate for determination of the residues of 9 β-agonists in porcine, bovine and ovine muscle and liver specimens.