We present a straightforward and accessible method to fabricate high density ZnO nanowires (NWs) with tunable morphology. Our approach includes (1) electrospinning of zinc salts embedded polymer nanofibers, (2) high temperature calcination for the polymer removal and the formation of ZnO seeds, and (3) hydrothermal growth of ZnO NWs. The high resolution transmission electron emission and selected-area electron diffraction characterization results indicate that the obtained ZnO NWs have a single crystalline structure. The method could be applied to produce highly dense and organized ZnO NWs with different pattern morphologies, including aligned, uniform film and hierarchical structured ZnO NWs mostly depending on the initial electrospinning conditions. The length of the ZnO NWs could be controlled in the range of 1-8 mu m by different growth time, which are able to generate the hydrophobic surface with different wetting properties. Due to the convenient preparation and large surface areas, the ZnO NWs fabricated by this method are suitable for a range of energy applications.