In this contribution, hierarchical micro-/meso-porous SiO2 xerogels were successfully prepared through a Stober methodology coupled with following drying process. The SiO2 xerogels were consisted of nanopartides of 20-40 nm in size with different contents of water. Fourier transform infrared spectroscopy proved that Si-OC2H5 and Si OH groups could be formed in SiO2 xerogels. Further analyses declared that the amount of the Si-OC2H5 groups decreased while the concentration of Si OH was firstly increased and then suffered a decline with improving contents of water. Besides, the SiO2 xerogels was endowed with controllable micro-/meso-porous structure. Furthermore, the formation mechanism of the micro-/meso-porous SiO2 xerogels was tentatively put forward. As a consequence, SiO2 xerogels with controllable hierarchical micro-/meso-porous structure could act as the smart material for huge development in catalytic fields. (C) 2017 Published by Elsevier B.V. on behalf of The Society of Powder Technology Japan. All rights reserved.