Abstract: TiAlCN films were deposited by direct current magnetron sputtering in order to study the composition, microstructure, mechanical and tribological properties as a function of direct current. The results show that with the increase of the direct current, the relative contents of element C reduced gradually, the contents of the amorphous carbon in the film decreased and the (Ti,Al)C_xN_1-x crystal grain increased. In addition, the surface roughness of the film was almost steady under a direct current of 3 A, and conversely, the surface roughness of the film increased suddenly as the direct current was increased. With the increment of the direct current, the hardness of the film increased firstly and then decreased, however the friction coefficient of the film decreased firstly and then increased. At the direct current of 3.5 A, the hardness and friction coefficient of the TiAlCN film were about 22.2 GPa and 0.16, respectively.