The study investigates major anti-oxidative constituents of ethanol extracts from the seeds of common buckwheat and tartary buckwheat.Ethanol extracts from buckwheat seeds were arranged to react with 1,1-diphenyl-2-picrylhydrazyl (DPPH)free radical.HPLC was used to identify anti-oxidative constituents of the ethanol extracts,and electro-spray MS was used to characterize the structures of these identified anti-oxidative constituents to confirm them.The ethanol extracts of common buckwheat and tartary buckwheat seeds both had DPPH free radical-scavenging effect;HPLC analysis showed that the ethanol extracts of both common buckwheat and tartary buckwheat seeds presented two main anti- oxidation peaks,which correspondingly had same chromatographic retention times and spectral information;electro- spray MS analysis showed that the molecular weights and MS fragmentation patterns of the anti-oxidative constituents in the ethanol extracts from buckwheat seeds were the same as those of turin and quercetin in the control samples.HPLC- MS/MS was capable of being used to rapidly identify anti-oxidative constituents in the extract of buckwheat seeds,and the main anti-oxidative constituents of buckwheat seed extract were mainly rutin and quercetin,and the anti-oxidative activity of quercetin was higher than that of rutin. The study investigates major anti-oxidative constituents of ethanol extracts from the seeds of common buckwheat and tartary buckwheat. Ethanol extracts from buckwheat seeds were arranged to react with 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. HPLC was used to identify anti-oxidative constituents of the ethanol extracts, and electro-spray MS was used to characterize the structures of these identified anti-oxidative constituents to confirm them. The ethanol extracts of common buckwheat and tartary buckwheat seeds both had DPPH free radical-scavenging effect ; HPLC analysis showed that the ethanol extracts of both common buckwheat and tartary buckwheat seeds presented two main anti- oxidation peaks, which correspondingly had the same chromatographic retention times and spectral information; electro- spray MS analysis showed that the molecular weight and MS fragmentation patterns of the anti-oxidative constituents in the ethanol extracts from buckwheat seeds were the same as those of turin an d quercetin in the control samples. HPLC-MS / MS was capable of being used to rapidly identify anti-oxidative constituents in the extract of buckwheat seeds, and the main anti-oxidative constituents of buckwheat seed extract were mainly rutin and quercetin, and the anti-oxidative activity of quercetin was higher than that of rutin.