The Kolbe reaction is one of the most classical electrochemical reactions, which enables carboxylic acids or carboxylates to undergo decarboxylation processes via anodic oxidation, forming dimeric alkanes. The reaction could be influenced by many factors separately or synergistically, and changing a single factor may completely change the reaction path. Platinum (Pt) and graphite are common electrode materials used in electrochemical reactions. Electrochemists have obtained abundant empirical evidence that the electrode materials surfaces can affect reaction paths and products, but conventional experiments have difficulty obtaining a microscopic understanding of the specific role of surfaces. In this work, we employ ab initio atomic models to simulate the Kolbe-type oxidation reactions of acetic acid as a model reactant on Pt and graphite surfaces from both thermodynamic and kinetic perspectives. An atomic-scale understanding is presented to explain why Pt and graphite electrode surfaces exhibit different preferences for reaction paths, and we also reveal the joint impact of surface morphologies and adsorption configurations on the kinetics of rate-limiting steps. For the surface morphologies, low-coordinated Pt atoms make the decarboxylation easier to happen on the Pt surface than on the graphite surface. The adsorption configuration of oxidative reaction intermediates is also a determining factor for the energy barriers of different reaction paths on the two surfaces. These discoveries provide mechanistic insights into the anodic oxidation of carboxylic acids, facilitating the understanding of microscopic electrochemical processes and the exploration of new electrochemistry.