Metastable-phase porous Zn2Ti3O8 nanorods as photocatalysts for overall water splitting, coupled with RuO2 as co-catalysts, were synthesized by using ethylene glycol as a phase-stabilizing and 1 D structure-directing agent. The typical electronic energy band gap of Zn2Ti3O8 was confirmed to be excellent for overall water splitting photocatalysts by theoretical calculations and experimental results. Steady and stoichiometric H2 and O2 evolutions were observed, which increased with time. The yields of H2 and O2 were near to 4 and 2 μmol h−1 (0.1 g), respectively. The excellent overall water-splitting activities could be attributed to the pure metastable phase of Zn2Ti3O8 possessing a suitable band gap and the porous 1 D structure favoring acceleration of the photogenerated charge transportation and separation.