The work aims to strengthen CrN film through solid solution by doping appropriate amount of Al, so as to improve the oxidation resistance and thermal stability of the film. High power impulse magnetron sputtering and pulsed direct current mag-netron sputtering were adopted to deposit Cr-Al-N films and the influence of different substrate biases on the structure and me-chanical properties of the coating was studied by XRD, indentation tester, film stress tester and friction tests. All CrAlN coatings exhibited a face-centered cubic (Cr,Al)N solid solution phase. As the substrate bias increased, the diffraction peaks growing along the (111) plane gradually weakened and shifted toward a small angle; the compressive stress of the film increased remarkably; the hardness of the film rose first and then decreased, and the hardness reached a maximum value of 22.3 GPa when the substrate bias was -30 V. The H/E value and the H3/E*2 value increased approximately linearly with the increase of the substrate bias voltage, and the maximum values were 0.11 and 0.21 at -120 V, respectively, and the friction coefficient and wear rate were gradually reduced. When the substrate bias is -120 V, the CrAlN film has the best wear resistance; H/E and H3/E*2 can be used to evaluate the wear resistance of the coating.