Abstract: A method based on the ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) has be developed for the determination of rhodamine B in zanthoxylum bungeanum maxim.The sample was extracted with 20 % acetone-normal hexane and then cleaned up by the Cleanert Alumina-N-SPE. The target analytes were separated on a C₁₈ column using acetonitrile and water containing 0.1% formic acid as the mobile phases, and were detected by a multiple reaction monitoring positive model.Under optimized detection conditions,the linear range for rhodamine B were 0.25~50 μg/kg.The linear equation was y=2800.6x-113.6,the coefficient of correlation was r=0.99993.The limits of quantification was 0.05 μg/kg. The relative standard deviations of reproducibility were 1.75%~2.29%. The recoveries of the method were 89%~102%. The method is simple, rapid, highly sensitive, and is suitable for the determination of rhodamine B in zanthoxylum bungeanum maxim.