The laser-induced chemical reactions on the surface of a polymer film were investigated by surface-enhanced Raman scattering (SERS) using chemically deposited silver as the SERS activating layer on the surface of the film. The silver-catalyzed pyrolysis at the outermost surface of the polyacrylonitrile film under laser radiations with different wavelengths was investigated by this SERS technique. The extremely low carbonization temperature at room temperature under laser implies several responsible mechanisms.