The invention discloses a preparation method for a co-doping DLC thin film. The preparation method is characterized by comprising the following steps that (1) a glass underlayer which is strictly washed correspondingly through acetone, ethyl alcohol, deionized water and the like is placed on a carrying table, and the carrying table exactly faces the focal point of target materials including wolfram W and graphite C; (2) the target materials of the W and the C incline at 45 degrees and align at the underlayer; (3) argon ion bombards the target materials, and thus the effects that surface impurities of the target materials are removed, and the target materials are activated are achieved; and (4) argon gas is pumped in to enable the target materials to simultaneously achieve build-up of luminance, and by changing parameters of each target material correspondingly, preparation of a W-doping diamond thin film with high performance is achieved. By changing technological parameters of each target material, the W-doping DLC thin films with the different doping amount and different performance can be prepared according to actual requirements.