One-dimensional ZnO nanostructures were considered as promising semiconductor materials for potential applications in optoelectronics. A number of methods have been used to fabricate ZnO nanostructures, such as chemical vapor deposition, vapor-phase transport, thermal evaporation, etc. However, these methods always have some disadvantage including the complex process, low reproducibility, high cost, etc, leading to the failures in the industrial applications. In this research, we developed a novel technique in which the ZnO rods were fabricated by re-crystallized from ZnO thin film. The ZnO nanorods with controllable density, growth direction, and high transparent were achieved. Finally, a dye-sensitized solar cell using obtained ZnO nanorods as photo electrodes was demonstrated, showing very good performance. Firstly, ZnO thin ?lms were deposited on TCO glasses by a conventional 13.56 MHz radio frequency magnetron sputtering system with optimized deposition condition. Secondly, the novel annealing processes were carried out for obtained ZnO thin films in a conventional furnace. The reducing annealing and oxygen annealing processes were shifted in order to control the balance of recrystallization of ZnO nanoros and reducing effect of ZnO thin film. The reducing gas was forming gas setting the ratio of 1.9% H2 in N2. According to the requirement of the different morphology (density, length, diameter, etc) of ZnO nanorods, the annealing temperature, time, and pressure were adjusted individually for each annealing process. As the summary, the ZnO nanorods could be grown in the novel annealing processes with well-controlled growth direction. The obtained ZnO nanorods showed good crystallinity and high transmittance. Through the investigation for different parameters during annealing processes, it was found that the oxygen annealing process between reducing annealing processes contributed to efficiently introduce the oxygen. With the annealing time controlling, the different morphologies of ZnO nanorods could be obtained. The low-temperature (less than 420ï¿½C) initial reducing annealing process contributed to control the density of ZnO nanorods. Moreover, the properties of different substrates were also found influencing on ZnO nanorods fabrication. The lower mismatch of the lattice imperfections and matching thermal expansion coefficient between ZnO film and substrates contributed to better crystallinity and vertical-alignment of ZnO rods. Finally, the obtained ZnO nanorods were used as photoelectrodes demonstrated in a dye-sensitized solar cell, which achieved the overall conversion efficiency of 5.48%.