A new method for the preparation of Fe2O3 nanoparticle/SiO2 microsphere composites is described, in whichfine alpha-Fe2O3 nanocrystals were prepared by forced hydrolysis of FeCl3 aqueous solution. The structureand optical spectra of these alpha-Fe2O3 nanocrystals have been studied. Their visible optical absorption canbe enhanced by their adsorptions on the surface of SiO2 microspheres and thereafter simple packing of thesemicrospheres to the aggregated structures. The size-dependent photogenerated surface photovoltage spectra(SPS) of these composites were studied, and quantum confinement effects of the SPS properties were observed.The transport of photoinduced charges between nanocrystals with intrinsic electronic nature of confined statesaccounts for this phenomenon. These results are helpful in understanding the relationship among d−d transitionand charge-transfer transition in transition metal oxides and find applications in photovoltaic devices.