High preferential c-axis oriented ZnO nanorods aligned on SiO₂/Si substrates with interdigital electrodes have been successfully fabricated through aqueous solution methods. The transparent ZnO buffer layer covered on both the conducting electrodes and the insulating SiO₂ spacer regions acts as lattice-matched template for the assembly of c-axis oriented ZnO nanorod arrays, and the subsequent growth of ZnO nanorods has been completed via a low temperature hydrothermal process. Detailed structural characterizations reveal that the as-synthesized nanorods are single crystalline, with a hexagonal phase, and with growth along the [0 0 1] direction. The gas-sensing properties of ZnO nanorod thin films are studied. It is found that the ZnO nanorod thin film sensor exhibits excellent sensing properties towards acetone at 300 °C with the response time shorter than 5 s.