A SrTiO₃ hetero-nanostructure was synthesized via solvothermal reaction using a protonated trititanate nanowire (H₂Ti₃O₇) and strontium hydroxide octahydrate (Sr(OH)₂·8H₂O) in an ethanol/water mixed solvent system. The ethanol to deionized water volume ratio was the controlling parameters for determining the phase formation and the particle size of the SrTiO₃ nanocrystals. Single-phase cubic perovskite SrTiO₃ began to form at 120°C in a mixed solvent containing >40% ethanol by volume. Field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HRTEM) showed that the as-prepared SrTiO₃ retained its wire-like (1D) morphology with nanocrystals (0D) on the surface. The synthetic mechanism of the 0D-1D SrTiO₃ hetero-nanostructures was demonstrated by topochemical reaction from dielectric tuning of the mixed solvent and the correlation between the crystal structures of SrTiO₃ and H₂Ti₃O₇. Using as-prepared SrTiO₃ nanowires, the photocatalytic activity for the degradation of a rhodamine B dye solution was evaluated under UV irradiation and compared to SrTiO₃ powder from solid state reaction.