Three ionones were isolated from the Rehmanniae Radix Praeparata,which were processed by the traditionally-adopted nine cycles of steaming and sun-drying,by using multiple chromatographic methods and their structures were elucidated as sec-hydroxyaegineticacid-2-O-β-D-glucopyranoside,frehmaglutin A,dihydroxy-β-ionone,from their spectral data and physicochemical properties.Among them,compound 1 is a new ionone glycoside.Compounds 2 and 3 were isolated from the Rehmanniae Radix Praeparata for the first time.The effect of compounds 1-3 on Human malignant melanoma A375 cell was investigated by MTT.The results showed that compounds 1-3 (25 μM) significantly inhibited the cell activities of A375 cells.