Surface-enhanced Raman spectroscopy (SERS) has become a promising technique widely utilized in the field of interface science due to its extremely high sensitivity and selectivity. Among this, surface plasmon resonance (SPR)-driven interfacial reactions have been attracted considerable attention because of their potential practical applications in the field of photocatalysis and photoelectrocatalysis. However, the relevant investigation was mainly focused on the single interfacial reaction for producing new compounds catalyzed by SPR or other external fields and it still remains significant challenge in designing of surface reaction and achieving the interfacial organic reaction with multi-steps. In this paper, 4-chlorothiophenol (4-CBT) was served as the probe molecule and glassy carbon electrode attached with gold nanoparticle monolayer film (Au MLF@GC electrode) was used as substrate due to its excellent uniformity. The extremely high surface sensitivity of SERS was utilized to realize the precise in situ monitoring of the interface catalytic reaction and its process with the synergistic effect of electrochemistry and SPR. In addition, several effects, involving potential, laser power, the pH value of solution and substituents, were systematically investigated. The results reveal that the surface catalysis reaction was absent by the control of single external field, such as potential or laser irradiation. In the relatively negative potential region, 4-CBT underwent a dechlorination reaction to produce thiophenol (TP) under the photoelectric synergistic catalysis, then dechlorination of 4-CBT was followed with a coupling reaction to generate biphenyl-4,4'-dithiol (4,4'-BPDT) as the potential further negatively shifts. The increase of laser power allows to significantly accelerate the reaction rate. The reaction rate is fastest in the neutral solution. Both 4-bromothiophenol (4-BTP) and ortho-or meta-dichloro-substituted thiophenol undergo similar dehalogenation substituents and surface coupling reactions. For ortho-dichloro-substituted thiophenol, the coupling efficiency is reduced due to steric hindrance. It provides a novel approach for surface multi-step organic synthesis reactions.