Abstract: A series of silver coated PET nonwovens was prepared by magnetron sputtering at room-temperature, the corresponding thickness of silver film were 25, 50, 75 and 100nm, respectively. X-ray diffraction measurements were carried out to examine the morphology of the silver films, it was found that the silver films form polycrystalline, crystal structure forms face-centered cubic; the mean size of Ag particles enlarges with increasing of film thickness; the spectrum and electric properties were also measured, the results indicated that there exists critical value of silver films thickness. Below the critical thickness, the reflectivity increases sharply while transmission rate decreases with the increasing of film thickness; but the change of reflectivity and transmission rate tend to a stable value when the film thickness reached at the critical value. The four- point probe test shows that the conductivity increases evidently with film thickness increasing via measurement of conductivity.