CrAlSiN/W 2 N nanolayered coatings were prepared by direct current magnetron sputtering. The modulation periods of multilayer coatings were controlled in the range from 3 to 20 nm. From the low angle x-ray diffraction and high angle x-ray diffraction (XRD) satellite peaks, the superlattice structure of these coatings was evidenced. The modulation periods of multilayer coatings were obtained precisely by the low angle XRD and high angle XRD satellite peaks methods. The detailed layered structure was further investigated by high-resolution transmission electron microscopy. Because of the dense and smooth nanolayered microstructure, the CrAlSiN/W 2 N multilayer films exhibited excellent microhardness. With an appropriate modulation period of 8 nm, the hardness reached a maximum around 40 GPa. The hardness enhancement is attributed to the large lattice mismatch and strengthening of superlattice structure, which is confirmed by XRD and transmission electron microscopy.