Abstract: TiO₂ nanoparticles were in-situ prepared on the solid/liquid interfacial adsorption layer. In the suspension of colloidal silica particles in binary mixtures of water/ethanol, a water-rich layer was formed on the hydrophilic surface of SiO₂. After phase equilibrium, dropping tetrabutyl titanate diffused into the adsorption layer and reacted with water. After centrifugation and drying, samples were obtained. The solvent-substituted experiment testified that reaction took place on the adsorption layer. TEM, XRD and electronic energy spectrum indicated uniform TiO₂ laid over the surface of SiO₂ particles. The effect of reaction temperature was investigated and potential mechanism was discussed.