This paper reports the correlation between the microstructure and the physical properties of transparent BaTi0.85Sn0.15O3 (BTS) thin films with thicknesses of 90-360 nm by radio frequency magnetron sputtering on the tin doped indium oxide (ITO)/glass substrate. All of the BTS/ITO/glass samples have relatively high optical transparency with over 75% in the visible light region. The dielectric constant and tunability of BTS films increase with thickness due to comparatively better crystallinity. The thicker BTS film is observed in an inter-diffusion between BTS film and ITO electrode from the result of secondary ion mass spectrometry depth profiling and then shown in a higher leakage current density. (C) 2013 Elsevier B. V. All rights reserved.