The work aims to refine the microstructure and improve the mechanical properties and anti-friction and anti-wear properties of the hydrogen-free diamond-like carbon (DLC) films by adjusting the bias. Ion beam assisted magnetron sputtering system was used to deposit DLC films with different bias. The surface morphology was observed by atomic force microscope (AFM), microstructure was analyzed by Raman spectrometer, hardness and elastic modulus were tested by nano-indentation apparatus, change of substrate curvature before and after deposition was measured by surface profiler and residual stress was calculated, binding force between films and stainless steel substrate was investigated by large load scratch tester, tribological properties of films were evaluated by TRB ball-plate friction and wear tester and profile of the film wear marks was measured by white light confocal microscope and the wear rate of the film was calculated. The bias had different effects on the surface morphology, microstructure, mechanical properties and tribological properties of DLC films. The increased bias lead to the increase of carbon ion energy and the surface roughness firstly decreased and then increased. When the bias was -400 V, the surface roughness of the DLC film reached the minimum and the C─C sp3 bond content was up to the maximum, which lead to the maximum hardness at this bias. The binding performance of the film was positively correlated with the carbon ions energy, and the optimal binding performance was 3.98 N when the bias was -800 V. The friction coefficient of the DLC film under different bias decreased obviously with the increased humidity. When the bias was -400 V, the DLC films showed the best friction properties in different humidity environment. When the bias is -400 V, the DLC film has the best comprehensive performance, and its surface roughness, hardness, binding force and friction coefficient are 2.5 nm, 17.1 GPa, 2.81 N and 0.11 respectively.