The invention provides a nano-multilayer film and a preparation method thereof. The preparation method adopts a vacuum sputtering technology; a sample stage and sputtering targets are arranged in a sputtering device; at least two sputtering targets jointly carries out sputtering deposition on the same sample stage at the same time, wherein a target material of at least one sputtering target is a diffusion element, and a target material of at least one sputtering target is a diffusion barrier element or a diffusion barrier compound; and when joint sputtering deposition is carried out, the sample stage rotates by itself. When the nano-multilayer film is prepared through codeposition, two or more targets focus on the same sample state at the same time, so that the multilayer film can be prepared without the need for switching different sample stages. The method is high in efficiency and lower in cost. The solid solution nano-multilayer film is obtained through codeposition instead of mechanical overlapping of pure Cu and pure W films with different crystal structures, and has an interfacehaving a semi-coherent or coherent relationship; and the interface is infiltrated, so that the plasticity, the toughness and the stability of the thin film are favorably improved.