Abstract: To establish a method for the analysis on the chemical components of Polygonum orientale flower by UHPLCESIQTOF MS.The analysis was performed on an Agilent Eclipse Plus C18 RRHD(2.1 mm×100 mm，1.8μm)column.The mobile phases were acetonitrile and water containing 0.1% formic acid in gradient elution at the flow rate of 0.4 mL/min.The mass spectra was obtain by Quadrupoletime of flightmass spectrometry under positive and negative ion modes and ESI ion source was used for qualitative analysis.The capillary voltages were set at 4.0 and 3.5 kV.The results indicated that 13 compounds had been identified by molecule mass information，reference data and present standards.The types of the compounds were phenolic acid,flavonoids and amides.The results show that the UHPLCESIQTOF MS is an effective divice to analyze the chemical constituents from P.orientale flower.

Key words: Polygonum orientale L.flower,  UHPLCESIQTOF MS, phenolic acid, flavonoids, amides