Synthesizing parameters in the hydrothermal method can affect directly the morphology and the contact angles of ZnO nanowires films, and thus the controllable wettability. In this paper effects of characteristic parameters on the properties of random rough surfaces are simulated, including arithmetical mean deviation of the profile, skewness, kurtosis and correlation length. Batches of ZnO nanowires films with varied morphology were synthesized in different concentrations of seed layer solution and growth solution, as well as growth time spans. Sampling length was determined and characteristic parameters of the profiles of ZnO nanowires films were extracted based on SEM micrographs and specific operators of Matlab software. With vertical and lateral parameters of the morphology introduced into Wenzel model, relationships between synthesizing parameters, morphology, and contact angles of ZnO nanowires films were established. It is conculded that the sampling length was determined to be 5 μm, crystallization between ZnO nanowires occurred as the concentration of growth solution was larger than 0.125 mol/L, resulting in hydrophobic ZnO nanowires films; different concentrations of seed layer solution and growth time spans led to hydrophilic ZnO nanowire films. These results can be used to immobilize various enzymes on ZnO nanowires films and further to improve the property of ZnO nanowires-based bio-sensors.