Identification of the active structure under reaction condition is of great importance for rational design of heterogeneous catalysts, but which is often hampered due to their structural complexity. This paper describes the interplay between the surface structure of Co3O4 and the CO2 hydrogenation reaction. Experimental results combined with theoretical calculations show that the Co3O4 with morphology‐dependent crystallographic surfaces presents different reducibility and formation energy of oxygen vacancies, thus resulting in distinct product selectivity. In reaction, Co3O4‐0h rhombic dodecahedra were completely reduced to metallic Co and CoO, which presents ~ 85% CH4 selectivity. In contrast, Co3O4‐2h nanorods were partially reduced to CoO, which exhibits a ~ 95% selectivity to CO. Furthermore, we demonstrate the crucial role of the Co3O4 structure in determining the catalytic performance for higher alcohols synthesis over CuCo‐based catalysts. As expected, Cu/Co3O4‐2h shows nine‐fold higher ethanol yield than Cu/Co3O4‐0h due to the inhibition for methanation.