Metallic plasmonic nanostructures have been widely investigated due to their unique optical controllability. In particular, the construction of large-area and uniform multi-metallic plasmonic nanoarrays with low cost has been a persistent pursuit. Herein, we proposed a simple method for the preparation of Au@Ag plasmonic arrays via polymer-nanoimprinting. Polycarbonate (PC) were reprinted with the pore structure of anodic aluminum oxide (AAO) template by hot melt embossed to form regular array of PC nanopillars. Then, a series of metallic plasmonic nanoarrays were obtained by depositing Au and Ag films with different thickness ratios on the top of the PC nanopillar. The uniform nanoarrays showed controllable near-field enhancing properties, and were employed as active surface-enhanced Raman Scattering (SERS) substrates, exhibiting good signal homogeneity (RSD ≈ 3.33%) for crystal violet (CV) molecules. This paper provides a simple, low-cost, and popularizing method for the preparation of SERS substrate with stable performance, having a good application prospect.