Photocatalytic reduction of NaAuCl4 by ethanol on the surface of mesoporous TiO2 films illuminated by UV light results in the formation of nanocrystalline TiO2/Au heterostructures with an average size of gold nanoparticles varying in a range of 20−60 nm depending on the photoprocess conditions. Raman spectra of the TiO2/Au heterostructures excited in the surface plasmon resonance bands of the Au nanoparticles were obtained. The TiO2/Au films pre-illuminated with relatively high power density of the laser beam used in Raman experiment (100 W/cm2) exhibit plasmonic enhancement of Raman scattering by titania excited subsequently with relatively low-intensity (10 W/cm2) laser light. This effect sheds some light on the mechanistic aspects of plasmonic photocatalysis observed for many gold-based metal-semiconductor heterostructures.