ZnO nanowires were synthesized via a vapor transport synthesis route. These nanowires were characterized by X-ray diffraction (XRD), field scanning electron microscopy (FESEM) and UV -- vis spectroscopy. The results of XRD revealed that monophasic nature of ZnO. The observation of FESEM images showed that the obtained ZnO nanowires were homogenous with average diameter of 30 nm. The photocatalytic activity of ZnO nanowire samples was studied by the degradation of Resazurin. The observed results showed that ZnO nanowires had a remarkable effect on the degradation of Resazurin under UV light. These results prove the potential use of ZnO nanowires for industrial waste water treatment.