The silver-modified sponge-like titanium dioxide arrays were prepared by a hydrothermal method. The effects of the hydrothermal reaction temperature, template agents were studied. The obtained products of Ag/TiO2 arrays were investigated by scanning electron microscope in combination with X-ray diffraction. Results show that polyvinylpyrrolidone plays a key role in the formation of titanium dioxide arrays. Compare to the commercial P25 (Degussa), the optimized TiO2 array-structures exhibit an obvious enhanced photocatalytic activity, that enhancement is attributed to its sponge-like biomimetic structure and silver modification. The products have potential applications in degrading organic pollutants.