The dependence of dielectric properties on the substrate temperature of the Bi1.5MgNb1.5O7 (BMN) thin films prepared on Au-coated Si substrates by the pulsed laser deposition technique has been investigated. It is shown that the substrate temperature has a significant effect on the structural and dielectric properties of BMN thin films. The deposited BMN thin films had a cubic pyrochlore phase when deposited at 600 degrees C or higher. A BMN thin film with an optimal substrate temperature of 700 degrees C has a medium dielectric constant of 106, a high tunability of 22.1% and a low loss tangent of 0.003. In addition, the effect of the substrate temperature on the leakage current of the thin films was also discussed. (C) 2014 Elsevier B.V. All rights reserved.