Abstract: The highly（110）-oriented（Ba_0.65Sr_0.35）TiO₃（BST）/CaRuO₃（CRO） heterostructure thin films on Pt/Ti/SiO₂/Si substrates were prepared by pulsed laser deposition（PLD）.The surface morphology of BST/CRO heterostructure thin film show many grain clusters,with cluster size up to 500 nm,which were composed by nano-sized grains in size of about 60-80 nm.It also revealed that a dense,homogenous,uniform microstructure,smooth and pinholefree surface morphology was obtained in the BST/CRO heterostructure thin films on Pt/Ti/SiO₂/Si substrates.The dielectric constant and tunabilities of BST/CRO heterostructure thin films were 851 and 78.1%,respectively.Compared with single composition BST thin films,the CRO bottom electrodes enhanced the dielectric properties and tunabilities.