High-ordered ZnO nano-rod arrays with an average length of about 1 pm and diameter of about 50-100 nm were vertically grown on indium-tin oxide (ITO) glass substrates using electrochemical deposition (ECD) method processing in a two-electrode cell at 85℃. The clear lattice fringes in the image of high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) showed that a single-crystal structure of ZnO nano-rods with the growth direction along the [0 0 2] direction. The cross-sectional field emission scanning electron microscopy (SEM) images results revealed that the deposition time played a key role in elongating the length of the ZnO nano-rods. A sharp peak in the UV region and a weak broad peak in the visible region between 400 and 500 nm were shown in the room temperature photoluminescence (PL) spectra of nano-rod arrays, suggesting the ZnO nano-rod arrays with high-quality crystals were obtained. This synthesis method provided an extremely low cost and easy route for the preparation of 1D ZnO nanostructures.