TiO2/PANI composite fiber films were fabricated by electrospinning, calcinations and in situ polymerization. The morphology and structure of the resulting composites were analyzed by scanning electron micrograph, transmission electron micrograph, Fourier transform infrared spectroscopy and Xray diffraction. It was found that this composite fiber film has a PANI nanowire-on-TiO2 nano/microfiber hierarchical nano/microstructure. The surface morphology of this hierarchical nano/microstructure was related to the structure of TiO2 nano/microfiber film, the time and temperature of in situ polymerization. Its photocatalytic property on methylene blue (MB) was studied, and the results showed that TiO2/PANI composite fiber film with this hierarchical nano/microstructure exhibited high photocatalytic activity for the degradation of MB under natural light. But both its photocatalytic activity and reusability were lower than those of pure TiO2 fiber film. To improve the stability and reusability of TiO2/PANI composite fiber film, a direct chemical bonding of PANI chains onto TiO2 surface, such as, the surface-initiated graft polymerization, is a useful method. (C) 2011 Elsevier B.V. All rights reserved.