Enzyme-mimetic metal-based catalysts have received extensive attention for the efficient catalytic applications. These catalysts can be adapted to complex environmental circumstances, thus becoming one of the effective ways to deal with refractory pollutants. In previous research, the K+-intercalated FeOCl (KxFeOCl) catalyst can produce Fe(IV)═O intermediate species through heterocleavage of H2O2 in a similar way as natural peroxidases. In this study, the detailed kinetics and surface reaction mechanisms of KxFeOCl were comprehensively investigated using 2-methoxyphenol (2-MeOP) as the model contaminant and at pH 7. 2-MeOP molecules are oxidized to organic radicals, which further oxidize 2-MeOP for direct radical–radical coupling. Based on the kinetics, the Langmuir–Hinshelwood model was used to describe the oxidative coupling of 2-MeOP on the KxFeOCl/H2O2 system. The competitive adsorption of H2O2 and downstream catalase activity of H2O2 decomposition were also proposed. The substrate oxidation rate of high-valent iron species reached 9.25 × 105 mM–1 min–1. These results clarified the intrinsic kinetic principle and interfacial reaction mechanism of 2-MeOP oxidative coupling catalyzed by KxFeOCl, offering valuable insights for optimizing reaction performance and scaling up the process.