Abstract In this paper, vertical aligned ZnO nanorod arrays were successfully grown by solution method onto seed layers of ZnO that fabricated by Langmuir–Blodgett (LB) method. The influences of seed layers (numbers of layers, fabricating routes, and with/without seed layers) and growing parameters (temperature, time and solution concentration) on morphology and orientation of ZnO nanorods were observed by SEM analysis results and discussed in details. XRD analysis results revealed that ZnO nanorods were preferred-oriented in (002) planes with wurtzite structure and highly crystallinity. UV–Vis transmission spectra showed the importance of the microstructures and the array degrees of ZnO nanorods to its optical properties. ZnO nanorods in good orientation led to higher transmittance and improved optical properties.