Abstract: The WC/a-C:H film was prepared by plasma-enhanced chemical vapor deposition combined magnetron sputtering. The structure and composition of the film were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and transmission electron microscopy. The tribological properties of the WC/a-C:H film in different emulsion systems were tested using a reciprocating friction tester. The results show that the WC/a-C: H film had a typical diamond-like structure and the WC was in the form of β-WC_1-X phase. The WC/a-C:H film preferentially grew on the (200) plane. The doping of WC in the carbon-based film changed the hardness and elastic modulus of the WC/a-C:H film to 11 and 140 GPa, respectively. Collaborative lubrication can enhance its wear resistance. The appropriate ratio and graphitization were the key factor affecting the friction.