Self-assembly ZnO nanorod array on Al-doped ZnO nanoplate surface is directly synthesized via a simple one-step hydrothermal approach, without using any template, surfactant or pretreated substrates. The morphology of the ZnO nanostructure observed by the scanning electron microscopy shows that the thickness and size of ZnO nanoplate are 200 nm and 2 m, respectively. The diameter and the length of ZnO nanorods are respectively 150 nm and 1.5 m. A possible growth mechanism is proposed for the selective growth of ZnO nanorods array on the nanoplate substrate, which contains two stage nucleation-growth processes. Finally, the influence of Al on the photoluminescence of the sample is been discussed.