TiO2 films embedding Au nanoparticles were prepared by the reactive magnetron sputtering method. Transmission electronic microscopy was used to study the structure of the films and the size of Au particles. The size and the density of Au particles had significant impact on dark specific resistance of the films. With the increasing number of Au particles, the specific resistance of the films experienced a rising phase, followed by a drop. The enhancement of photocatalytic reactivity of the films was attributed to the contact of a metal-conductor. Based on the experimental results of the photocatalytic reactivity of the films, the mechanisms of the change of dark specific resistance were studied. It was found that the increase of specific resistance with the incorporation of Au particles was ascribed to the Schottky barrier rather than to the size quantization effects of Au nanoparticles.