We synthesize a large area of ZnO nanorod array by using the RF magnetron sputtering and low-temperature hydrothermal method. The sample morphology, crystal structure and optical properties are characterized and analyzed by means of the SEM, XRD and fluorescence spectrophotometer. The results show that ZnO nanorod array has the advantages of large aspect ratio, ordered orientation, uniform and compact at a lower OH⁻/Zn²⁺ concentration. The XRD results show that the samples are all hexagonal wurtzite structures and the photoluminescence (PL) pattern shows that an obvious ultraviolet peak of the samples appears around 375 nm, and an emission band of strong yellow green light appears in the wavelength between 450–650 nm. With the increase of the concentration ratio of OH⁻/Zn²⁺, the ultraviolet peak and the emission band of strong yellow green light both show a blue shift. The above results indicate that the ZnO nanorod array is a type of potentially preferred materials for ultraviolet optoelectronic devices.