The invention relates to a method for depositing a metal or hard ornament film on a plastic substrate. In the method, the metal or hard ornament film is prepared on the surface of a plastic substrate material by using a radio frequency magnetron sputtering technology, and good binding force exists between the prepared ornament film and the substrate. The plastic substrate material comprises ABS plastic (terpolymer of acrylonitrile-butadiene-styrene), PMMA (polymethyl methacrylate) organic glass, PE (poly ethylene) plastics, PP (polypropylene) plastics and the like. The metal ornament film comprises chromium, nickel, titanium, aluminum, aurum, silver, iridium or alloys and the like, and the hard ornament film comprises metal nitrides, carbon compounds, oxides, diamonds and the like. The method has the advantages of simple operation, no pollution and low cost, and the prepared film is good in adhesive force.