CrAlSiN nanocomposite coatings with different structures were prepared by arc ion plating. The influence of substrate bias on the composition, microstructure and properties of the coating was investigated. The nanocomposite CrAlSiN coatings all had a fcc-(Cr, Al)N phase, where Al atoms and some Si atoms were solid-dissolved in CrN phase and some Si existed in the form of amorphous phase in the coating. The coatings were preferentially grown along the (200) crystal plane. With the increase in substrate bias, the roughness of the coating gradually decreased. When the substrate bias gradually increased to 100 V, the small particles aggregated into large particles, producing more holes, so that the surface roughness of the coating increased. At the same time, with the increase in substrate bias, the hardness and adhesion of the coating first increased and then decreased. When the substrate bias voltage was 80 V, the coating had the largest hard H (31.30 GPa), elastic modulus E* (432.15 GPa), H/E* (0.0724), H³/E*² (0.1642) and binding force of 109.26 N.