A novel methodology based on the dissolution-growth mechanism was developed to prepare ZnO nanowires films. The film morphology and structure were investigated by using field emission scanning electron microscopy, high-resolution transmission electron microscopy and X-ray diffraction analysis methods. The results show that the ZnO nanowires are single crystalline c-oriented wurtzite. The ZnO rod crystals were eroded to provide the growth primitive of ZnO nanowires, which formed on top of the rod crystals when the erosion reaction got the equilibrium. The length of the resultant nanowires is rather large because the successive erosion of the rod crystals maintains the low concentration of Zn2O(OH)2n−2 in the aqueous solution.