DLC (diamond-like carbon) films were prepared on Ti/PMMA(polymethyl methacrylate) under the different bias; the principal purpose of this study is to explore structural differences of films on Ti/PMMA with and without conductive material, and to further clarify the role of the conductive Ti interlayer in influencing the deposition mechanism. The results indicate that the films deposited on Ti/PMMA with conductive material exhibit uniform DLC structure and mechanical hardness when the bias voltage is ≥550 V. Furthermore, the deposited DLC does not change the wettability of PMMA, while the addition of the Ti interlayer virtually increases the risk of peeling off of the film. The results of the tribological study demonstrate the films on Ti/PMMA with conductive material have better tribological properties than those without conductive adhesive. This research work can provide basic theoretical guidance for depositing uniform DLC films on PMMA and even on all non-conductive substrates.