Abstract: Ag-doped ZnO thin films were fabricated on silicon substrate with different Agdoping concentrations by sol-gel method. The samples were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible spectrophotometer and current-voltage measurement, respectively. The effects of Ag doping on the structure, surface topography and electrical properties of ZnO thin films were investigated. The results showed that the elemental Ag is generated in ZnO thin films with the addition of Ag and the increasing of the doping concentration, and a new absorption peak appears at 404nm, which is probably induced by the formation of Ag nano-particles. At the same time, the conductivity of Ag-doped ZnO thin films is obviously improved and the film transmittance in the visible region is all above 85%. When the doping concentration is 7at%, the sample shows the best conductivity with visible transmittance greater than 90%.