A method was developed for the determination of fumonisin B1，fumonisin B2 and fumonisin B3 in feeds by high performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS）.The samples were extracted with acetonitrile-water-formic acid（50∶49∶1,by volume）,and cleaned up with a PRIME HLB solid phase extraction column.The analytes were separated on an Agilent Zorbax SB-C18 column（150 mm×2.1 mm,3.5 μm） and gradiently eluted with acetonitrile and 5 mmol/L ammonium acetate solution containing 0.1% formic acid as mobile phases.The target compounds were detected with electrospray ionization（ESI） in positive mode under multiple reaction monitoring mode,and quantified by the external standard method with matrix correction standard curves.The results indicated that the linear ranges for 3 compounds ranged from 5.0 μg/L to 250.0 μg/L with correlation coefficients（r2） more than 0.995.The limits of detection（LODs） and quantitation（LOQs） were 3 μg/kg and 10 μg/kg，respectively.The average recoveries at three spiked levels of 10，20 and 50 μg/kg were in the range of 80.3%-93.7%,with relative standard deviations（RSDs） of 7.5%-13.4%.The method is simple,rapid and stable,and could be used for the detection of fumonisins in feeds.