Well aligned zinc oxide (ZnO) nanorods (NRs) on ITO substrate for photoelectrochemical application were synthesized successfully through two steps preparation which consisted of deposition ZnO NPs by sol-gel spin coating at 3000 rpm for 40 sec. then followed by cost-effective simple hydrothermal method. The study investigates the effect of growth temperature and duration on the optical properties, photoconversion efficiency, and morphological structure of ZnO/ITO NRs. The hydrothermal temperature was varied between 80 °C to 120 °C and the growth time between 1 to 5 hours. The results of X-ray diffraction showed that the samples had a single hexagonal phase with a strong (002) preferred orientation. ZnO NRs prepared at 110 °C showed the highest diffraction peak intensity with crystallite size of 30.07 nm which implies the excellent crystallinity obtained at this temperature. FE-SEM proved that the temperature and growth time critically affect the diameter and the length of NRs. Photocurrent density of 0.337 mA/cm2 at +0.5 V vs Ag/AgCl reference electrode shown by ZnO NRs photoelectrode prepared at 110 °C for 4 hours which is about 8 times greater than ZnO nanoparticles.