Abstract: AISI-1045 steel was duplex surface modified by deposition of a Si-B-N composite film based on triode-radio frequency-direct current negative bias voltage-plasma enhanced chemical vapor deposition (RF-DC-PECVD) and a MoS_2-based film based on radio frequency sputtering. The composition and structure of the Si-B-N composite thin film were analyzed by means of X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy. The friction and wear behavior of the Si-B-N film was investigated and compared to that of Si-B-N/MoS_2 film on a ball-on-disc test rig, and the critical load of the film was determined on a scratch tester. It was found that the structure and properties of the Si-B-N film were highly dependent on the DC negative bias voltage applied onto the substrate during the sample-preparation process. The Si-B-N composite film was composed of h-BN and c-BN which had much larger hardness than the steel substrate and were able to form interfacial transition layer with the steel substrate, and hence the tribological behavior of the steel was greatly improved. Moreover, the friction and wear behavior of the Si-B-N film was further significantly improved by the introduction of the sputtered MoS_2 film, which was attributed to the excellent transfer adhesion and self-lubricity of the MoS_2.