The Rutile nanorods (NRs) TiO2 for water splitting applications were prepared on Si, FTO, and silicon nanowires array (SiNWs) by hydrothermal method. A three-electrode system and solar simulator were used to measure the photocurrent of water splitting. In order to investigate the relationship between the morphologies of TiO¬2nanorods and the photo currents during bias, difference hydrothermal temperatures, precursor compositions, synthesized times, and various annealing conditions were performed. The currents of theTiO2NRs grown on FTO were optimized. Unfortunately, whenTiO2 NRs prepared on Silicon and SiNWs as the substrate, forming a three dimensional TiO2 structure, the negligible photocurrent were measured. To understand the reason of the current decrease, Mott-Schottky measurement and X-ray photoelectron spectroscopy (XPS) were used to show that at the interface of silicon and TiO2 the titanium did not complete oxidized. Instead of Ti film fully oxidized, silicon substrate was oxidized in the afterward annealing stage.