In this paper, we prepared TiO2 thin film with the surface modified by a connected Au micro-grid via a microsphere lithography strategy, and the modified films show higher photocatalytic activity than the pure TiO2 film. The photocatalytic activity improved as Au loading increased, obtaining the best performance at a certain loading amount, and then decreased at higher loading amount. This behavior, not observed in TiO2 films modified with Ag micro-grid, can be attributed to the relationship between the energetic positions and the metal clusters size.