Three-dimensional(3D)flower-like anatase TiO2 nanostructures and flower-like titanate nanostructures were successfully synthesized via hydrothermal synthesis followed by post-treatment from titanium powder.The flower-like anatase TiO2 nanostructures were characterized in detail with scanning electron microscopy(SEM),X-ray diffraction(XRD),UV-vis spectrum and nitrogen adsorption-desorption measurement,respectively.It is found that the flower-like TiO2 nanostructures have a high specific surface area and a large light-harvesting efficiency.The photocatalytical activity of the flower-like anatase TiO2 nanostructures was determined by degradation of methylene blue in aqueous solution,and was compared with commercial P25 titania.It is revealed that the photocatalytical activity of the flower-like anatase TiO2 nanostructures is enhanced a lot.The apparent rate constant of the flower-like anatase TiO2 nanostructures is almost 2 times that of P25 titania.