ZnO nanorod arrays were prepared in an open system by using a simple aqueous solution method. Spindlelike, wimble-like, tower-like and hexagonal rod-like ZnO rods were obtained under different conditions. ZnO nanorod arrays with different morphology and size were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and contact angle measurement (CAM). The size of ordered zinc oxide rods can be controlled by temperature of water bath, because this temperature can influences growing speeds in different crystal directions. Some additives, such as urea and thiourea, were introduced into reaction solution to improve quality of arrays. Surface character of ZnO nanorod arrays can be changed from hydrophilic to hydrophobic, which was proved to be dependence on size of air grooves on surface.