Abstract Both gold and silver nanoparticles have a characteristic of surface-enhanced Raman scattering (SERS). Poly(L-lysine) is a water-soluble polypeptide composed of naturally occurring L-lysine, which contains an amine group on each side chain. The side chain amino group of surface-grafted poly(L-lysine) with positive charge can adsorb nanoparticles to form nanocomposite films. These films can be used as a template for surface-enhanced Raman scattering (SERS). We use Rhodamine 6G to find the effects of film to SERS.