The metabolites of astragalin in blood were rapidly analyzed and identified by ultra-high performance liquid chromatography-tandem time-of-flight mass spectrometry (UPLC-Q-TOF-MS).After administration of astragalin,the drug-containing serum samples were collected at the different time from the orbital venous plexus of rats.The data were collected by the high-resolution mass spectrometry.The mass spectrometric decomposition of astragalin and its metabolites were systematically studied by PeakView,Metabolite Pilot and ChemBioDraw software,what clarify the biological transformation process of astragalin and its metabolites in rats.The results showed that there are two metabolic pathways of astragalin in the rats.One is Ⅰ phase metabolic,which included hydration,oxidation,reduction and methylation.Another is phase II metabolism,which included glucuronidation,sulfation and glutathione-bound.And 20 metabolites were detected in the drug-containing serum samples，including 18 hydrolysates,what is consistent with its glucoside structure.The method was rapid，simple and sensitive，and can be used to explain the metabolism and transformation of astragalin in rats.All of these maybe provide reference for the pharmacodynamic material basis,new drug development and clinical application of astragalin.