A large aligned nanorod array of alpha-Fe2O3 grown on FTO substrate was prepared via a simple hydrothermal synthesis method. The photoelectric property of the array was studied by surface photovoltage technique. Based on the photovoltage responses on spectrum, we discussed the transfer characteristics of the photogenerated charge at the surface of the nanorods and the interface between the nanorods and the FTO substrate. The contributions of surface states and built-in electric field were discriminated. Moreover, the quantum size effect on the photovoltage spectra could be observed only when the array was illuminated from the free surface of the nanorods. (c) 2008 Elsevier B. V. All rights reserved.