Revealing the nature of plasmon-exciton co-driven surface catalytic reactions is important and urgent for developing potential applications in energy and environmental science. In this work, we propose a mechanism for plasmon-exciton co-driven surface catalytic reactions based on our experimental results. We provide a method for a unified treatment for reduction and oxidation reactions, which not only strongly supports our proposed mechanism but also promotes a deeper understanding of plasmon-exciton co-driven surface catalytic reactions.