Cr-Ti-Si-N coatings were prepared using unbalanced magnetron sputtering via adjusting Si target powers. The microstructure and mechanical properties were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM) and nano-indenter, respectively. The tribological properties of Cr-Ti-Si-N coatings sliding against SiC balls in air were investigated using ball-on-disk tribometer. The results indicated that the high hardness of the coatings (34.9-48.3 GPa) was due to solution strengthening and nanocomposite structure. More volume fraction of a-SiNx in Cr-Ti-Si-N coatings at a high Si content resulted in a decrease of coating toughness (5.19 MPa.m1/2) and local peeling off. The friction coefficient decreased from 0.87 to 0.67 with an increase of Si target power, while the decreased toughness of coatings weakened anti-wear properties of coatings at a high Si content.