Abstract: Monolithic AlN,BN films and AlN/BN multilayers were prepared by reactive RF magneron sputtering on Si substrate.The films were characterized by X-ray diffraction,fourier transform infrared spectroscopy,high-resolution transmission electron microscopy and atomic force microscopy.The results showed that the AlN/BN multilayers preferred (103) orientation,and it was strengthened with the increase of BN layer thickness.Monolithic AlN and AlN/BN multilayers showed island growth type.The interface roughness and surface roughness of AlN/BN multilayers decreased with the increase of BN layer thickness.The structure of BN layers dependeded on the thickness of BN layers.The w-BN crystalline was successfully prepared when the thickness of AlN was 4.0 nm and the thickness of BN was in the range of 032-0.55 nm,and it was amorphous when the thickness of BN was over 0.74 nm.