Boron nitride(BN) films for high-frequency SAW devices were deposited on n-type Si(100) wafers by changing the process parameters using RF magnetron sputtering.The structure of hexagonal boron nitride(h-BN) films was investigated by Fourier transform infrared(FTIR) spectroscopy and X-ray diffraction(XRD) spectra.The surface morphology and piezoelectric properties of h-BN film were characterized by atomic force microscopy(AFM).And the results show that when the RF power is 300 W,the substrate temperature is 500 ℃,working pressure is 0.8 Pa,nitrogen and argon flow ratio is 4∶20 and negative substrate bias is-200 V,h-BN films are in high purity and c-axis oriented,and the particles are uniform and compact,and the roughness is 2.26 nm with even piezoelectric response,meeting the requirements of high sound propagation speed and excellent piezoelectric properties for high frequency SAW devices.The studies of piezoelectric test of thin films have shown that the PFM test method of atomic force microscopy is suitable for characterizing piezoelectric properties and piezoelectric response distribution of nano-structure semiconductor thin films.