A method of forming a metallic pattern on a polymer substrate is provided. A mixture layer is formed on a polymer substrate surface. The mixture layer includes an active carrier medium and nanoparticles dispersed in the active carrier medium. A laser process is performed to treat a portion of the mixture layer to form active seed residues on the surface of the polymer substrate. A cleaning process is performed to remove an untreated portion of the mixture layer to expose the surface of the polymer substrate, while the active seed residues are remained on the surface of the polymer substrate. Then, the active seed residues on the polymer substrate are subjected to an electroless plating process to form the metallic pattern over the active seed residues on the polymer substrate.