An ideal catalyst that can be used for the selective catalytic reduction (SCR) of NO at low temperature should have a high activity and ability to resist SO₂. Herein, Ti-doped Fe₂O₃ (Ti-Fe₂O₃) nanoparticles that extraordinarily convert NO (T₉₀, 200 °C) and highly resist SO₂ meet this requirement. In the presence of 100 ppm SO₂, the optimal Ti-Fe₂O₃ can convert 90% NO at 220 °C for 24 h. With the addition of Ti⁴⁺, the electrons around Fe³⁺ migrate toward Ti⁴⁺, strengthening the electron-deficient tendency of Fe³⁺. Therefore, electron-donating NH₃ is preferentially adsorbed by Fe³⁺, endowing Ti-Fe₂O₃ with the ability to resist SO₂ and exceptionally tolerate SO₂ at low temperature. Besides, based on the strength of the embedded Ti⁴⁺, a large number of Brønsted acid sites are converted to Lewis acid sites to speed the reaction rate of SCR below 210 °C. High anti-SO₂ capacity and adequate Lewis acid sites maximize the efficiency of Ti-Fe₂O₃ in reducing NO.