Abstract: The silver nano-crystals doped silicate glass was prepared by direct current electric field-assisted thermal diffusion of silver ions into the silicate glass sheet followed by annealing in air. The results show that the content of silver ions diffused into the silicate glass increases with the increase electric field intensity and diffusion temperature. The silver particles exist as the state of Ag⁺ and Ag⁰ through DC electric field assisted diffusion. It was found that most of the silver nano-particles locate in the depth between 30 to 100 nm with a mean size of 2～5nm. The surface plasma resonance （SPR） peak,which belong to silver nano-crystal,was shown near 410nm in the transmittance spectrum of the glass sheet.