Effects of photoinduced electron transfer on the Raman spectroscopy of Alizarin (Alz) dye-sensitized TiO2 nanoparticles were investigated by theoretical and experitmental methods. The results indicate that red-shift of absorption spectra and quenching of the fluorescence spectra are attributed to the photo-induced electron transfers from the excited state of the absorbed Alz dye molecules and the charge transfer complex (Alz/TiO2) to the conduction band manifold of the TiO2 nanoparticles. The resonance Raman spectroscopy of the Alz dye-sensitized TiO2 nanoparticles reveals that the ultrafast photoinduced interface electron transfer significantly enhances the C=C, C-O, and C=O bond stretching vibrations of the absorbed Alz dye molecule at the interface.