Abstract: CO₂ methanation is a very complex heterogeneous catalytic process, in which a variety of intermediates are produced. There are still many controversies and contradictions in the exploration of the reaction pathway of CO₂ methanation. In-depth and systematic study of the evolution process of the intermediates formed on the catalyst surface in CO₂ methanation will help to further optimize the design of catalyst from the perspective of mechanism, thereby improving the catalytic performance. This paper summarises recent work on the CO₂ methanation reaction pathway based on in situ infrared spectroscopy, focusing on the influence of the active metal, carrier, additives and synthesis method of the supported catalyst on the CO₂ methanation reaction pathway and the resulting positive effects on catalyst performance. In addition, the controversial points faced at the current stage, such as the activation sites of reaction gases CO₂ and H₂, the active sites of catalysts and the feasible research methods in the future are discussed in detail.