Quality Ba0.8Sr0.2TiO3 (BST) thin films with a remnant polarization of about 3.5μC/cm2,and a coercive field of about 53kV/cm have been successfully prepared by a sol-gel processing using a 0.05mol/L precursor solution.X-ray diffraction and field emission scanning electron microscope investigations show that the BST films exhibit a tetragonal structure (c/a=1.009) and consist dominantly of large columnar grains of about 150nm in diameter.The observed good ferroelectricity and insulating property render the sol-gel derived BST thin films promising for uncooled infrared detector and thermal imaging applications.