0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 (PMN-PT) thin films with a special Pb(Zr0.2,Ti0.8)O3 (PZT)/PbOx bilayered buffer layer have been grown on Pt/Ti/SiO2/Si(100) substrates by rf magnetron sputtering technique. Pure perovskite crystalline phase with highly (100)-preferred orientation, determined by x-ray diffraction, was formed in the PMN-PT thin films. The highly (100)-oriented PMN-PT thin films prepared by using this method possess very good ferroelectric properties with a high remanent polarization Pr (Pr=32 μC/cm2) and a low coercive field Ec (Ec=62 kV/cm). Moreover, the relative dielectric constant as high as 1595 is obtained in the PMN-PT thin films at 1 kHz. The experimental results indicate that the PZT/PbOx buffer layer plays an important role in the crystal orientation, phase purity, and electrical properties of the PMN-PT thin films.