Abstract: Mathcad software is used to simulate the mathematical model of the Solidly Mounted Film Bulk Acoustic Resonator(SMR-FBAR) device.The effects of different piezoelectric film materials and thickness,different electrode materials and thickness on the resonance characteristics of FBAR devices are analyzed.The aluminum nitride(AlN) film was prepared by RF magnetron sputtering.The piezoelectric properties of AlN film were tested by Piezoelectric Force Microscope(PFM).The resonant frequency of the composite FBAR is lower than the ideal resonant frequency due to the increased electrode thickness factor.The electromechanical coupling coefficient of the piezoelectric material plays a decisive role in the device bandwidth.The electromechanical coupling coefficient of the device is proportional to the electromechanical coupling coefficient of the material.AlN has a high piezoelectric coefficient,which can effectively improve device performance and increase bandwidth,and is suitable as a piezoelectric film material.Using small piezoelectric thin film and thin electrode is beneficial to increase the frequency of devices.