Mesoporous silica fibers were prepared by varying primary variables of the synthesis conditions in the static two-phase acidic system such as the hexane/Si(OR)4 and HCl/Si(OR)4 ratios as well as the alkyl chain length of silicon alkoxide. The morphological and structural features of the mesoporous silica materials were strongly dependent upon the hydrolysis rate of silica source used. Namely, the high fraction of well-ordered mesoporous silica fibers was achieved by a delicate balance of the hydrolysis rate of silicon alkoxide and the condensation rate of silica species. The obtained mesoporous silica fibers consisted of hexagonally organized channels running circularly around the fiber axis. The fibers prepared with Si(OC4H3)4 showed the high thermal stability because of the lower content of structural defects within the framework.