The invention relates to a preparation method for a co-doped diamond-like carbon film. The preparation method comprises the following steps that ultra-white glass with the thickness of 0.3-0.5 mm is selected as a substrate material; the substrate material is ultrasonically cleaned; a W target and a C target are set, the W target and the C target are set in an intersecting manner, and the intersecting point of the two targets is located at a sample holder; the cleaned super-white glass substrate is placed on the sample holder; the W target and the C target are subjected to Ar ion bombardment, and the functions of cleaning and activating the targets are achieved; the cleaned substrate material is put into a sputtering chamber of which the vacuum is pumped to 3.0x10<-4>-5.0x10<-4> Pa, argon is introduced into the sputtering chamber, pre-sputtering luminance build-up is conducted, and meanwhile nitrogen is introduced. The preparation method has the beneficial effects that the W target andthe C target are independently controlled, the process parameters and the amount of nitrogen of the two targets are changed, various high-performance films can be prepared, the preparation process issimple, the experiment is easy to control, and the films different in hardness and transmittance can be prepared according to the actual needs.