Design and fabrication of nanoscale semiconductors with regulatable morphology or structure has attracted tremendous interest due to the dependency relationship between properties and architectures. Two types of SrTiO₃/TiO₂ nanocomposites with different morphologies and structures have been fabricated by controlling the kinetics of hydrothermal reactions. One is TiO₂ nanotube arrays densely wrapped by SrTiO₃ film and the other is SrTiO3 nanospheres distributed on the top region of TiO₂ nanotube arrays, which has been firstly fabricated. It has been found that the photoelectrochemical performances of these heterostructures are crucially dominated by their architectures. Heterostructured SrTiO₃/TiO₂ nanotube arrays were fabricated by traditional method in the absence of NaOH and they exhibited higher photoelectrochemical performance than pure TiO₂ nanotube arrays. However, the compact SrTiO₃ coating film on the sidewalls of TiO₂ nanotube arrays could inevitably destroy the tubular structures of TiO₂ and thus go against the vectorial transport of electrons. Interestingly, when excess NaOH was added into the growth solution, SrTiO₃ nanospheres would be rationally grafted on the top of TiO₂ nanotube arrays, which could preserve the tubular structures of TiO₂, and thus further improve the photoelectrochemical performance.