Construction of composite metal interfaces with synergistic catalysis is an important research field for CO preferential oxidation in H2 steam (CO-PROX). Microwave electromagnetic loss can effectively compensate the thermal action on the active interface derived from metal-organic frameworks (MOFs). Herein, a trimetallic CuCoCe-MOF is derived to construct Cu–Co–Ce oxidation active interface oriented by magnetic, conduction and relaxation loss, which inhibit the high temperature deactivation due to sintering. Equipped with the tandem microwave pyrolysis, the intermediate CuCoCe/C fully exposes electromagnetic characteristic and heterogeneous interfaces. Subsequently, microwave strengthened CuCoCeOx exhibits an excellent CO-PROX activity window with the more than 85% CO conversion within 80–210 °C. Besides, in-situ Raman and in-situ DRIFTs investigations demonstrate that the equilibrium of active interfacial oxygen vacancy via hydrogen is crucial for the temperature window broadening of CO-PROX. This work provides a route for the efficient conversion of microwave electromagnetic energy to enhance the active interface for synergistic catalysis.