Silver nanowires with high yield, uniform size and high aspect ratio were successfully synthesized by a simple and effective polyol method under low temperature and quiescent conditions, adopting CuCl2·2H2O as the nucleation control agent for the first time. The synthesized silver nanowires were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-Vis diffuse reflectance spectroscopy (DRS). The results indicate that the silver nanowires were composed of face-centered cubic structure of pure metallic silver with high crystallinity. And the silver nanowires have an average length of 80~100 μm and an average diameter of 40~80 nm. Thus, the aspect ratio of the nanowires was greater than 1000. In addition, the influence on the morphology and structure of the silver nanowires were investigated for reaction temperature, mole ratio of PVP:AgNO3, molecular weight of PVP and mole ratio of control agent CuCl2 · 2H2O:AgNO3. Finally, the optimum reaction condition were obtained for the preparation of the silver nanowires with high aspect ratio.