In this study, a new kind of Si-B-N composite film was deposited on 1045 steel with good adhesion by radio frequency-direct current-plasma enhanced chemical vapor deposition and then was analyzed by X-ray photoelectron spectroscopy and X-ray diffractometry. The results indicate that through the appropriate control of process parameters, especially applying a DC negative bias voltage to the substrate, the Si-B-N composite film with a mixed phase of h-BN and c-BN crystal is obtained. The film was produced by duplex treatment, and its performance was then evaluated. The effects of the applied negative bias on the BN content, adhesion strength, microhardness, and friction coefficient were also investigated.