To study the chemical constituents of the ethanol extraction from Bidens Pilosa.Methods:The chemical constituents of the ethanol extraction from Bidens Pilosa were separated and purified by silica gel chromatography，Sephadex LH-20 chromatography and C18 reverse phase silicon chromatography，and the chemical structure was identified by 1H-NMR，13C-NMR and mass spectrometry.Results:A total of 6 compounds were isolated，purified and identified from the ethanol extraction of Bidens Pilosa：quercetin-3,3'-dimethyl ether-7-O-β-D-rhamnopyranoside(1)，okanine-4'-O-β-D-(2″,4″,6″-triacetyl)-glucopyranoside(2)，4-O-(6″-O-p-coumaroyl-β-D-pyranone glucose)-p-coumaric acid(3)，4-O-(2″-O-acetyl-6″-O-p-coumaroyl-β-D-pyranone glucose)-p-coumaric acid(4)，isopropyl phthalate(5)，protocatechuic acid(6).Conclusion:The above 6 compounds were first isolated from Bidens Pilosa.Among them，4 compounds—quercetin-3,3'-dimethyl ether-7-O-β-D-rhamnopyranoside(1)，4-O-(6″-O-p-coumaroyl-β-D-pyranone glucose)-p-coumaric acid(3)，4-O-(2″-O-acetyl-6″-O-p-coumaroyl-β-D-pyranone glucose)-p-coumaric acid(4)，isopropyl phthalate(5)the above 4 compound were the first to be isolated and identified from the medicinal plants of Bidens L.