The effect of various substrates on the formation of epitaxial Pb(Mg-1/3, Ta-2/3)O-3 (PMT) thin films has been investigated. Pb(Mg-1/3, Ta-2/3) O-3 thin films were prepared on SrTiO3 (STO), LaAiO(3) (LAO), and MgO substrates by the chemical solution deposition (CSD) method. Microstructural evolution of PMT thin films as a function of annealing temperatures (650-750 degreesC/1 h) has been studied using the transmission electron microscopy, the scanning electron microscopy, and the X-ray diffraction (XRD). Epitaxial PMT thin films could be grown on STO and LAO substrates with an epitaxial orientation relationship of [100](001)(films)parallel to[100](001)(substances). However, pyrochlore phase was mainly observed and no epitaxy nature was observed in PMT thin films on MgO substrates. The difference in the epitaxy nature is explained in terms of the difference in the lattice mismatch and the crystal structure. (C) 2004 Elsevier B.V. All rights reserved.