Abstract: The low temperature TiO2 sol with polystyrene (PS) microspheres as template for porous structure was coated on raw and alkali deweighting PET fibers by impregnation, and a series of photocatalytic TiO2/PET fibers were prepared. The TiO2 and fibers were characterized by XRD and SEM. The photocatalytic performance of TiO2/PET fibers was evaluated through degradation of methyl orange. The results indicated that nanometer anatase TiO2 with high photocatalytic activity was obtained after the sol aging. The TiO2 loading on PET fiber surface increased with the increasing proportion of TiO2 sol in impregnating solution. The alkali deweighting of PET fibers contributed to improving TiO2 loading and photocatalytic activity. With TiO2 loading rate increasing, the degradation rate of methyl orange increased from the beginning and then decreased slowly. The TiO2/PET fiber showed best photocatalytic activity with the loading rate of 4.2%. Porous TiO2 film due to PS as template can further enhance the specific surface area and the adsorption ability of photocatalytic fiber, so as to improve the photocatalytic activity.