Plasmon-mediated　chemical　reaction　(PMCR)　is　a　highly　attractive　field　of　research.　Here　we　report　in　situ　surface-enhanced　Raman　spectroscopic　(SERS)　monitoring　of　plasmonic-mediated　S-S　bond-forming　reaction.　The　reaction　is　thought　to　be　a　self-coupling　reaction　proceeding　by　photoinduced　aromatic　S-C　bond　arylation.　Surprisingly,　the　S-C　arylation　and　S-S　coupling　are　found　to　be　occurred　on　both　partially　oxidized　silver　and　silver　nanoparticles.　The　results　demonstrated　that　silver　oxide　or　hydroxide　and　small　molecule　donor　sacrifice　agent　played　a　crucial　role　in　the　reaction.　This　work　facilitates　the　in-situ　manipulation　and　characterization　of　the　active　silver　electrode　interface　in　conjunction　with　electrochemistry,　and　also　establishes　a　promising　new　guideline　for　surface　plasmon　resonance　photocatalytic　reactions　on　metal　nanostructures　with　high　efficiency.