In the non-aqueous acetonitrile solution, recurring to the confocal Raman system, we studied the catalysis and oxidation of carbon monoxide on the surface of platinum electrode utilizing surface-enhanced Raman spectrum (SERS). As the movement of the potential, the process of the catalysis and oxidation interacted with the surrounding molecular. In the present paper, the catalysis and oxidation of carbon monoxide on the surface of platinum electrode was not clearly observed, but also the dissociation of acetonitrile was discovered simultaneously. Results show that acetonitrile decomposition occurs at a certain more negative potential by the appearance of the 2,133 cm-1 bands assigned to CN stretching modes. The bands observed at ca. 502 and 2,055 cm-1 are attributed to the Pt-CO(nu Pt-c) and intramolecular C-O(nu C-O) stretching vibration respectively, suggesting linearly adsorbed CO on platinum. The main product of COads oxidation is confirmed to be carbonate due to the existence of trace water in the double-layer region as a source of oxygen for the reaction.