MS/MS fragmentation patterns of five flavone di-C-glycoside standards from Viola yedoensis were studied by ultrahigh performance liquid chromatography-electrospray ionization-quadrupole time of flight-mass spectrometry（UPLC-ESI-QTOF-MS/MS） in the negative ion mode.The fragmentation pathways of C-6 and C-8 sugars in these flavone di-C-glycosides were consistent with those reported earlier.The results of our study also suggested that the configurations of sugars at C-8 obviously influenced the fragmentation behaviors.The fragmentation behaviors of these flavone di-C-glycoside standards were successfully used to characterize flavone C-glycosides in V.yedoensis.Total of 21 flavone di-C-glycosides along with 4 flavonol O-glycosides were identified or tentatively identified on the base of their MS/MS data，accurate molecular weights，or by comparing with reference standards.The UPLC-ESI-QTOF-MS/MS method is rapid，sensitive and accurate,and could be used for the characterization of flavone C-glycosides in traditional Chinese medicines.