TiO 2 is an important photocatalyst candidate for solar energy or hydrogen energy harvesting. Creation of porous structures or high surface area within TiO 2 microspheres may potentially address the challenge to improve their efficiency. In present work, we report the sol–gel fabrication of mesoporous TiO 2 microspheres that assembled from nanoparticles with the assistance of gelatin template. The phase structure, morphology, and mesoporous characteristics were analyzed by X-ray diffraction, transmission electron microscopy, and BET measurements. Particularly, the gelatin-assisted fabricated TiO 2 nanoparticles (∼10–20 nm) were achieved to assemble TiO 2 microspheres with diameters of 0.2–0.5 μm, which yielded a typical type-IV BET isotherm curve (N 2 hysteresis loop) with a large surface area of 98.3 m 2 /g and a small pore size of 11.9 nm. A simplified model was proposed to investigate the effect mechanism of gelatin on the formation of TiO 2 mesoporous microspheres. The room temperature pressure-dependent hydrogen evolution of the gelatin-assisted fabricated TiO 2 nanostructures has also been investigated, suggesting that gelatin favors high surface area and improves the hydrogen storage performance, and the achieved TiO 2 microspheres could be potential candidates to be utilized as the photocatalyst for hydrogen evolution.