A liquid-liquid phase transfer method was employed to prepare novel nano titanium oxide/silicone oil organosol. First, titanium oxide nanoparticles were synthesized in aqueous phase and then modified with several surfactants. It is found that only sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl sulphate (SDS) can cap nanoparticles and then nanoparticles could be transferred into organic phase by the phase transfer method. The transfer process was certified by the rapid change of color for the aqueous and organic phase. Other surfactants including hexadecyltrimethyl ammonium bromide (CTAB) and oleic acid were unable to ensure the phase transfer in the organic phase. The procedure was also verified by high-resolution transmission electron microscopy (HRTEM), particle size analyzer, UV-vis, etc. The results also showed the narrow size distribution of the nanoparticles. The mechanism of phase transfer is also discussed for different surfactant. Because of its good antisedimentation and high electrorheological effect, organosol is a novel path for the design and application of electrorheological fluid. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 3763-3769, 2008