Three new acetylated C-glycosylflavones, 3aEuro(3),6aEuro(3)-di-O-acetylswertiajaponin (1), 4aEuro(3),6aEuro(3)-di-O-acetylswertiajaponin (2), and 6aEuro(3)-O-acetylswertiajaponin (3), together with six known compounds were isolated from the whole herb of Swertia mileensis. Their structures were elucidated on extensive NMR experiments and mass spectrometry studies. H-1 and C-13 NMR data exhibited doublet signals at room temperature. Variable temperature H-1 NMR experiments were carried out to investigate the presence of rotational isomerism of C-glycosylflavones. All compounds showed potential antioxidant activities against apoptosis of H2O2-induced human embryo liver L02 cells.