Silver oxide film was electrodeposited onto the indium tin oxide (ITO) glass. X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy were used to determine the structure. The argentic oxide was identified to be AgO. Surface enhanced Raman scattering (SERS) spectra of 4-mercaptobenzoic acid (4-MBA) were obtained on the AgO film after the 514.5-nm laser activation. Ag nanoparticles produced from the photo-active decomposition of AgO was the substrate responsible for the enhancement of Raman signal of 4-mercaptobenzoic acid. The evolution of 4-MBA SERS spectra with time was observed due to development of Ag nanoparticles against the activation time. SERS spectra of 4-MBA, p-aminothiophenol (PATP) and benzoic acid (BA) were analyzed to determine the adsorption and orientation behaviors of above molecules. Both the electromagnetic and chemical enhancement mechanisms were proposed to be responsible for the observed enhancement of Raman signals. The enhancement factor for 4-mercaptopyridine (4-MPY) was estimated on the order of magnitude of 103.