The influence of Fe2O3 on the SNCR deNO(x) process was investigated in a fixed-bed reactor. The experimental results demonstrated that Fe2O3 has an inhibitory effect on the SNCR deNO(x) process that is more notable at low temperatures. Interactions between Fe2O3 and NH3, Fe2O3-catalyzed NH3 oxidation, and NO reduction by NH3 were studied experimentally. In the absence of O-2, Fe2O3 was reduced by NH3 to form Fe, which then catalyzed NH3 decomposition to N-2 and H-2. Fe2O3 also catalyzed NO reduction by NH3. In the presence of O-2, Fe2O3 mainly catalyzed NH3 oxidation. All reactions showed first-order characteristics with respect to NH3, which indicates that the adsorption of NH3 and its dissociation into -NH2 on the surface of Fe2O3 is the rate-controlling step in these processes. The presence of O-2 and NO affected the selectivity of further -NH2 reaction. A kinetic model was developed, and the simulation results agreed well with the experimental data.