Development of reliable and stable process for synthesis of nanowires is an important step in the field of application on nanotechnology. One of the options to achieve this objective is to use chemical process such as solvothermal method. Silver nanowires have been successfully synthesized by reducing silver nitrate (AgNO3) with ethylene glycol (EG) in the presence of Trioctyl phosphine oxide (TOPO) as the capping agent at 120ºC for 2 hrs. Electron microscopy, X-ray diffraction, and absorption spectra have been used to investigate the products, and the mechanism is proposed to interpret the controlled synthesis of silver nanowires. The results indicate that this approach provides a versatile route to prepare silver nanowires with controllable diameters. The formation of nano products by this method is rapid, simple and stable.