Lead magnesium niobate titanate (Pb[(Mg1/3Nb2/3)(0.9)Ti-0.1]O-3; PMN-PT) thin films were prepared on Pt/Ti/SiO2/Si substrates with buffer layers by pulsed laser ablation (PLA). Lead titanate (PT), barium titanate (BT) and barium strontium titanate (BST) were chosen as the materials of the buffer layer. The crystalline structure of the PMN-PT thin films on the buffer layers was a mixture of perovskite and pyrochlore phases. Among these samples, the PMN-PT thin films on the BST buffer layer have the highest perovskite fraction of over 95%. Average dielectric constant of the PMN-PT thin film on the BST buffer layer was about 1200. No serious interdiffusions between the bottom electrode, the buffer layer and the PMN-PT layers were observed.