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Two kinds of magnetic iron oxides (Fe2O3-PO and Fe2O3-AO) are synthesized via the solution combustion coupled with the chemical oxidization of hydrogen peroxide. The magnetic carbon-containing Fe2O3-AO obtained at the absence of air presents the main γ-Fe2O3 crystal with smaller crystallite size and larger BET surface area, but not the aggregated and sintered α-Fe2O3 crystal of Fe2O3-PO. The doping of tungsten has no effect on the growth of α-Fe2O3 in Fe2O3-PO during the annealing process at 400 °C. However, the doping of tungsten effectively restrains the irreversible transformation of γ-Fe2O3 into α-Fe2O3 crystal and enhances the anti-collapse of the pore structure of Fe2O3-AO under the same annealing process at 400 °C by inducing a stronger interaction between tungsten species and γ-Fe2O3 crystal. In addition, the doping of tungsten improves the ratio of surface adsorbed oxygen, the Fe2+/(Fe2++Fe3+) ratio and the surface acidity of Fe2O3-PO-400 and Fe2O3-AO-400. Therefore, the doping of tungsten promotes the catalytic performance of Fe2O3-PO-400, especially its high-temperature activity, but exhibits a better promotional effect on the low-temperature activity of Fe2O3-AO-400. Magnetic 5W/Fe2O3-AO-400 shows the highest BET surface area, the largest Fe2+/(Fe2++Fe3+) ratio, the strongest surface acidity and the appropriate redox ability compared with the other tested catalysts, thus exhibits the highest low-temperature NH3-SCR activity and better resistance to SO2 and H2O than 5W/Fe2O3-PO-400. The formation of low crystallinity and high dispersive γ-Fe2O3 is an important reason on the good catalytic performance of magnetic 5W/Fe2O3-AO-400, which is also confirmed by the influence of annealing temperature. Furthermore, the results of steady-state kinetic experiments demonstrate that the 5W/Fe2O3-AO-400 catalyst mainly follows the Eley-Rideal mechanism.