Abstract: A new approach for determination of 13 kinds of sedatives in animal derived food by automatic solid phase extration combined with ultra performance liquid chromatography- tandemmass spectrometry using isotope internal standard was described.The homogenized sample was spiked with diazepam- d5 and chlorpromazine- d6,and extracted with acetonitrile,then purified by automatic solid phase extration. After the analytes were separated by Waters ACQUITY UPLCTMBEH C18( 2.1 mm × 100 mm,1.7 μm) column.All sedatives were detected by MS/MS system with eletrospray ion ization( ESI+) under multiple reaction monitoring( MRM) mode and quantified by the isotope internal standard technique.The result indicated that the LOD of 13 kinds of sedatives ranged from 0.030μg / kg to 0.113 μg / kg.Meanwhile,the high correlation coefficents( r≥0.999) of 13 kinds of sedatives were obtained within their respective linear ranges. The average recoveries at low,intermediate and high spiked levels ranged from 88.5% to 115.0% with relative standard deviations( RSD) of 2.45% ~ 7.92%. The method with simple sample preparation achieved the automated purification process which then improved considerably the work efficiency.This method was suitable for simultaneous determination of multiple sedatives in animal derived food with simple pretreatment,high sensitivity,good recovery.