Bi1.5Zn1.0Nb1.5O7/(111)-oriented Ba0.6Sr0.4TiO3 [BZN/BST (111)] bilayered films (similar to 500-nm-thick) have been prepared on Pt/TiOx/SiO2/Si substrates by RF-magnetron sputtering. Experimental results suggested that the BZN layer has played a positive role in improving the dielectric properties of the films. With the increased thickness of BZN, the dielectric loss was significantly lowered, accompanied with a tolerable reduction of tunability. The thickness effect was discussed with a series connection model of multilayered capacitors, and the calculated permittivity was obtained. At 400 kV/cm, moderate tunability of 50.55%, low dielectric loss of 0.0108, and the largest figure of merit of 46.8 can be achieved for BZN (50 nm)/BST(450 nm) bilayered films.