A novel and facile method to prepare hydrophobic nano-silver colloid and aqueous coordinate was proposed. Chemical reduction of silver nitrate in a tributyl phosphate (TBP) solution containing polyvinylpyrrolidone (PVP) was conducted and stable hydrophobic nano-silver/TBP/PVP colloids were obtained. Adopting a phase transfer process, the as-prepared colloids can be diverted into an aqueous system to obtain hydrophilic nano-silver colloids. The resultant materials were characterized by digital camera, TEM, XRD and UV-vis spectra. The results show that the reaction can be accomplished fast at room temperature and the synthesized colloids can remain stable for a long time, and the mean diameter of silver particles is around 10 nm for both nano-silver colloids. The nano-silver crystalline is face-centered cubic (fcc) structure, and the UV-vis absorbance peaks are at 412 and 420 nm for aqueous nano-silver and nano-silver/TBP/PVP colloids respectively. (C) 2010 Elsevier B.V. All rights reserved.