By way of electrospinning followed by annealing at different temperatures, TiO2 nanofibers with different phases have been successfully fabricated. The corresponding ultraviolet photocatalytic activity was evaluated using rhodamine B degradation as a probe reaction. The photocatalytic activity of TiO2 nanofibers is found to be enhanced when annealed at higher temperatures with amount of anatase phase transformed to rutile. An optimal annealing temperature exists on the photocatalytic activity of TiO2 nanofibers, which increases with the increasing of the calcination temperature up to 600 degrees C and then decreases. According to their phase transformations monitored by X-ray diffraction, the different crystalline structures could be the reason for the enhanced photocatalytic activity of these electrospun TiO2 nanofibers.