Ordered [C/CoPt/Ag]5 thin films with (001) preferred orientation have been deposited onto glass substrates by magnetron sputtering. The effects of the Ag layer on the structural and magnetic properties of the [C/CoPt/Ag]5 films were investigated. We have found that the presence of C sublayer together with the suitable thickness of Ag sublayer can provide a driving force for the chemical ordering of the L10 CoPt phase, as well as give an opportunity for the (001)-oriented growth of CoPt grains. It was found that the structural and magnetic properties of CoPt films are strongly related to the strain arising from the misfit between Ag and CoPt layers as well as the C atom diffusion. These three element composite films with a high (001)-oriented growth, a strong perpendicular magnetic anisotropy, and a weak intergrain interactions can satisfy the requirements for ultra-high-density perpendicular recording medium.