In this work, we demonstrate a new and simple method for preparing Au nanowires by ethanol reduction of hydrogen tetrachloroaurate (HAuCl 4 ) without additional capping agents by a thermal process. The resulting products were investigated by UV–vis spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results indicated that the size and shape of the Au nanocrystals could be controlled by systematic variation of the experimental parameters including the concentration of HAuCl 4 in the reaction solution, heating temperature and reaction time. We suggest that this method introduced in our work may be more practical for the large-scale synthesis of shape-controlled metal nanomaterials.