CoCrMo alloys are widely used as artificial joint implants due to their excellent mechanical properties, good wear resistance and outstanding corrosion resistance. However, the risks of release of cobalt and chromium ions urge researchers to improve the wear resistance of implants further by using surface modification technology. Diamond-like carbon film with 3.0 μm thickness was deposited on the surface of CoCrMo alloy using ion-source-assisted magnetron sputtering. The friction coefficients of the CoCrMo alloy decreased remarkably under different conditions after the formation of diamond-like carbon film. After the deposition of diamond-like carbon film the wear rates of the CoCrMo alloy decreased by 52.4 %, 47.1 % and 49.4 %, under dry friction, physiological saline, and bovine serum lubrication, respectively.