In this communication, we report an innovative electrode design of 3D hierachical TiO₂ urchin assembled with a hollow TiO₂ spheres core and radial TiO₂ nanorod shell prepared via a facile colloid template route combined with atomic layer deposition and a hydrothermal growth process. The periodically hierarchical TiO₂ urchin exhibits excellent omnidirectional anti-reflectance properties in a wide range of wavelengths and angles of incidence (AOI). When tested as a photoanode for PEC water splitting, a greatly improved photoelectrochemical water splitting performance is obtained in comparison to that of TiO₂ microspheres due to the improved light harvesting and charge collection efficiency.