The photocatalytic reactivity and the surface wettability of highly transparent TiO2 thin films prepared by an ionized cluster beam deposition method were investigated, focusing on their surface morphologies, surface areas, and crystal phases. The As-prepared TiO2 thin films showed higher photocatalytic reactivity, greater roughness in surface morphology and a larger surface area than the films calcined at temperatures higher than 823 K. Furthermore, the As-prepared film exhibited efficient photoluminescence (PL) spectra at 77 K, showing prolonged lifetimes for the photo-formed electron-hole pairs. Detailed discussions on the interaction between the PL intensity and photocatalytic reactivity as well as the surface wettability have been carried out from the viewpoint of the physicochemical properties of the TiO2 thin films.