In this paper,an analytical method were developed for the determination of 5 main flavone aglycones including quercetin,luteolin,kaempferol,apigenin and baicalein,in Lonicerae Flos by solid phase extraction and liquid chromatography tandem mass spectrometry(SPE/LC-MS/MS).In Lonicerae Flos samples,rutin,cynaroside,astragalin,rhoifolin and baicalin were hydrolyzed and extracted by 50% ethanol solution(contained 10% hydrochloric acid),refluxed for 120 min,and finally cleaned up with an HLB solid phase extraction column.The solution was separated on a Mightysil RP-18 column(150 mm×46 mm(id),3 μm),and determined by LC-MS/MS with negative electrospray ionization(ESI-) in multiple reaction monitoring(MRM) mode.The external standard method was used for the quantitation analysis of 5 main flavone aglycones.The limits of quantitation(LOQs,S/N=10) were 0005 g/kg for quercetin,001 g/kg for luteolin and apigenin,and 005 g/kg for kaempferol and baicalein.Single laboratory method validation data were determined,and the calibration standard curves for 5 flavone aglycones were linear in the range of 0-10 g/kg with correlation coefficients more than 0995.The recoveries,at there spiked levels of 01,02,04 g/kg for quercetin and luteolin,005,01,02 g/kg for kaempferol,apigenin and baicalein after hydrolysis,ranged from 704%to 104%with relative standard deviations of 40%-12%.This method was suitable for the simultaneous determination and confirmation of flavone aglycones in Lonicerae Flos.