ZnO-Au_(25) nanocomposites were synthesized by doping Au_(25) nanoclusters into the porous Zn O nanospheres. It was notable that the ultrasmall Au_(25) nanoclusters possessed uniform sizes and fine dispersibility on the porous ZnO supports. A considerable correlation between the loading of Au_(25) nanoclusters and the photocatalytic activity was found. Compared with the pure ZnO nanospheres, the ZnO-Au_(25) nanocomposites exhibited more efficient photocatalytic activity in terms of degradation of Rhodamine B(RhB) in an aqueous solution. In addition, the possible photocatalytic mechanisms are discussed in this work. This strategy may be helpful for preparing other novel hybrid nanocomposites with well-defined structures and superior performances. It was not able to the ultrasmall Au 25 nanoclusters possessed uniform sizes and fine dispersibility on the porous ZnO supports. A considerable correlation between Compared with the pure ZnO nanospheres, the ZnO-Au 25 nanocomposites exhibited more efficient photocatalytic activity in terms of degradation of Rhodamine B (RhB) in an aqueous solution. In addition, the possible photocatalytic mechanisms are discussed in this work. This strategy may be helpful for preparing other novel hybrid nanocomposites with well-defined structures and superior performances.