Abstract：Au@Pt core-shell nanoparticles were successfully synthesized via the seed-mediate growth method and were self-assembled to be a monolayer film at the water/hexane interface. After being carefully transferred onto a glassy carbon (GC) electrode, a monolayer film electrode was fabricated with high Au@Pt surface-to-volume ratio. It was found that good dispersion of Au@Pt core-shell nanoparticles on the surface of GC electrode was achieved, resulting in the uniform monolayer film electrode. It was resulted that the as-prepared monolayer film electrode exhibited high electrocatalytic activity for methanol oxidation. Moreover, the monolayer film exhibited excellent surface enhanced Raman spectroscopic (SERS) activity due to the long-range enhancement effect from the Au nanoparticles core, which was well recognized as a good SERS substrate. Therefore, it can be served as a SERS substrate for investigating the surface adsorption and reactions at the molecular level. According to these advantages of the monolayer film electrode, the reaction process of methanol oxidation was monitored by in situ SERS detection via combining the strong SERS activity and the high electrocatalytic activity of the monolayer film electrode. The data supplies the basis on analyzing the mechanism of methanol oxidation on Au@Pt film/GC electrode.