Relaxor-based 0.7Pb (Mg1/3Nb2/3) O3-0.3PbTiO3 (PMN-PT) thin films were grown epitaxially on silicon substrates by sol-gel method and PbO cover coat technique, and investigated by x-ray diffraction, auger electron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The phase development and microstrure evolution of the PMN-PT film were significantly affected by the final annealing temperature and time. A perovskite PMN-PT film was obtained after annealing at 850℃ for 1min. Then, highly <100>-oriented and textured PMN-PT films could be achieved by using a LaNiO3 perovskite template.