In this work, a low temperature ( 178°C) ultraviolet (UV, 1000W) decomposition process was employed to fabricate the ZnO nanowires on a flexible of PET substrate under ambient air using Zn(AcAc)2 as a precursor. HRTEM image revealed that the nanowires consisted of single crystalline ZnO nanoparticles in the range of ∼5–15 nm. On the basis of the SEM image, the nanowires' diameter is ∼20–120 nm with the length up to several thousand microns long. X-ray diffraction pattern reveals that the nanowires exhibit a single phase of crystalline structures and belongs to ZnO hexagonal wurtzite with lattice constants a = 0.33 nm and c = 0.52 nm. The growth mechanism of the the ZnO nanowires is governed by a self-assembly oriented attachment process. The ZnO nanowires can be fabricated on a flexible photodetector with a high photocurrent to dark current ratio ∼3800%.