Abstract: The phase transition and phase composition of TiO₂ coating layer in the TiO₂/muscovite nanocomposites were studied by Raman spectrum.The results showed that amorphous Ti(OH) 4 transform directly into rutile phase under suitable accelerant Sn⁴⁺ ions,not anatase phase.In the TiO₂/muscovite nanocomposite,TiO₂ coating layer contains both rutile and anatase,but rutile is dominant.The Raman spectra of TiO₂ coating layer showed stronger Raman scattering,and confirmed the polycrystalline feature of TiO₂ particles.With increasing of TiO₂ layer thickness,size of TiO₂ particles increase,their crystallization degree increase too.