Lead magnesium niobium titanate (PMNT) thin films with a composition near the morphotropic phase boundary were prepared on conventional Pt(111)/Ti/SiO2/Si substrates using a modified sol-gel process. A PbO seeding layer was introduced to the interface between the PMNT layer and the substrate to enhance the [001]-preferential orientation of the PMNT film. Single-phase perovskite PMNT films with highly [001]-preferential orientation were obtained at reduced annealing temperatures compared with the PMNT films directly deposited on the same substrates. The dielectric and ferroelectric properties of the prepared PMNT films were evaluated as a function of annealing temperature.