Abstract: The chromium transition layer, CrN intermediate layer and CrTiSiN-Ni composite films with different nickel atomic fractions (0.5%, 1.6%, 5.6%, 9.6%, 14.4%) were fabricated on YG10 hard alloy matrix by non-equilibrium magnetron sputtering. The effect of nickel content on the structure, mechanical properties and tribological properties of the composite films was studied. The results show that the crystalline phases of the composite films with different Ni content mainly consisted of face-centered cubic CrN/TiN, and a portion of ni was solid-solved in the matrix phase, once the solid-solution limit was exceeded, it existed as pure phase. With the increase of ni content, the hardness, elastic modulus and fracture toughness of the composite film first increased and then decreased. The hardness reached the maximum (27.1 GPa) when the Ni atomic fraction was in range of 1.6% to 5.6%, and the fracture toughness was the largest (3.56 MPa · m^1/2) when the ni atomic fraction was 5.6%. With the increase of ni content, the average friction coefficient of the CrTiSiN-Ni composite film increased, the wear scar became wider and deeper, and the wear resistance decreased.