Mesoporous TiO2 nanomaterials have been investigated for decades; however, most endeavors have been focused on the exploration of their potentials in various applications, and the fundamental research for preparing mesoporous TiO2 in a highly controllable manner remains unfruitful. Herein, we report a facile pressure-driven oriented assembly approach to synthesize an unprecedented type of dehiscent mesoporous TiO2 microspheres with radial mesopore channels and oriented rutile crystallites. By varying the concentrated HCl amount, we have been able to produce TiO2 microspheres with well-controlled rutile/anatase phase ratio. By further manipulating the reaction conditions including solvent evaporation time and hydrothermal temperature, the oriented growth with tunable crevices can also be well manipulated. Such dehiscent mesoporous TiO2 microspheres have exhibited great permeability and excellent photocatalytic properties for H2 generation. We believe that the high structural complexity and predictability of this method offers great opportunities in enhancing the performance of TiO2-based materials. The development of porous materials and their applications has been in great demand recently. However, the progress in rational synthesis of porous semiconductors remains unproductive. Here, we have demonstrated a hydrothermal method to synthesize a novel type of mesoporous TiO2 microsphere with highly controllable structure. By regulating the synthetic conditions, the mesoporous TiO2 can be well controlled with oriented mesopores and lattices, tunable crystalline phase, and tailored open crevices. The resulting mesoporous TiO2 microspheres exhibit excellent penetration properties and photocatalytic activities, which is attributed to their unique mesostructures associated with accessible high surface area and particular architectures. Such a simple method, which is able to fabricate mesoporous TiO2 with controlled architectures and crystallites, is expected to be applied to produce numerous delicate nanostructures at moderate conditions for potential applications, such as catalysts, energy storage, and biosensors. We have demonstrated a facile hydrothermal approach to synthesize a novel type of mesoporous TiO2 material with highly controllable structure. By regulating the synthetic conditions, the mesoporous TiO2 can be well controlled with desired crystallites and architectures. The resulting mesoporous TiO2 exhibits excellent penetration properties and photocatalytic performance. These unique mesoporous TiO2 microspheres produced at moderate conditions could afford great opportunities in achieving high performance in various practical applications.