New narrow band gap semiconductor cobalt titanate (CoTiO3) nanorods are fabricated via an ethylene glycol-mediated route and further calcination in air. The glycolate precursors and porous CoTiO3 nanorods are investigated in detail by using SEM, TEM, XRD, thermogravimetric, FTIR, and UV/Vis spectroscopy and N2 adsorption–desorption isotherm. The effect of calcining temperature is also studied, and 700 °C is found to be the optimal calcining temperature used to prepare porous CoTiO3 nanorods with high crystallinity and porosity as well as excellent photocatalytic performance in water oxidation under visible light irradiation. The highest oxygen production yield is up to 64.6 μmol h−1 without co-catalysts. The high photocatalytic activity for oxygen production is ascribed to the following reasons: 1) the large surface area, which favors absorption and offers more active sites, 2) the suitable narrow band gap, which can use more solar energy, and 3) the 1 D structure, which leads to good electron transport.