Abstract: A method to detect the residues of clenbuterol, ractompamine, salbutamol,cimaterol and terbutaline in beef and ox liver is developed. The sample is extracted after enzyme digestion, and purified and enriched using solid phose extraction，then analyzed qualitatively and quantitatively under the MRM mode. The method has a lower limit of detection of 0.2μg/kg, and a quantitation of 0.4μg/kg. The average recoveriy of standard addition levels (0.5,1,2μg/kg) ranged in 78.2％~114.2% with relative standard deviations between 2.0％~16.0％.The method is fast, economic, accurate and sensitive,it is suitable for the rapid qualitative and quantitative detection of β2-agonist in beef and ox liver.