The dielectric properties of Ba0.65Sr0.35TiO3(BST) films deposited by an electron beam assisted ionized cluster beam epitaxy (ICBE) technique were investigated. Highly (110) oriented BST films having a thickness up to 1, um have been successfully grown on a Si (100) substrate at 400°C using the electron beam assisted ICBE system with a plasma O2 source. It was found that the dielectric constant increases from 475 to 1191 with different process conditions. A BST film with a thickness of 500Å deposited at a substrate temperature of 400°C has a dielectric constant of 1191 and a leakage current of about 2.37×10-9 A/cm2. This shows the BST film can be applied to dielectrics of ULSI capacitors.