It is a great challenge to realize direct decomposition of NO at low temperature and high efficiency under complex sintering flue gas conditions. A GeO₂/MgCo₂O₄ - 40% BaCO₃ catalyst is developed for the efficient direct decomposition of NO in microwave catalysis under the condition of low temperature with excess O₂ and some SO₂ and CO₂, and then the denitration performance and sulfur resistance of the catalyst are investigated. XRD and TEM characterization are used to analyze the catalyst deactivation and the reason for the improvement of the deactivation after modification. The results show that the denitrification rate of the microwave catalyst is almost stable when the volume fraction of CO₂ in the inlet gas is 5%. After GeO₂ is introduced, the sulfur resistance of the microwave catalyst is obviously improved. Under the atmosphere of 0.1% SO₂ volume fraction and the reaction temperature is only 250 ℃, the microwave catalyst can achieve 99.9% NO conversion and 99.9% N? selectivity. TEM results show that there is no obvious difference in the topography features of the catalyst before and after the reaction. The new denitration method of direct decomposition of NO by microwave catalysis established in this paper can provide a new way for green deep denitration under complex flue gas condition.