TiO2 and alpha-Fe2O3 nanoparticles were covalently coated with an organic chromophore monolayer, 4-(4-N,N-(dialkylamino) styrl pyridium using trimethoxyl (p-(chloromethyl) phenyl) silane as linkage molecules. The resulting composite particles were characterized by UV-vis, IR, X-ray photoelectron spectroscopy (XPS), and surface photovoltaic spectroscopy (SPS). All the results indicated the formation of the organic-inorganic hybrid structures. The photoinduced interfacial charge transfer in the composite particles were also detected by SPS under different external voltages imposed.