Selective catalytic reduction (SCR) of NO from simulated flue gas by ammonia with Fe 2 O 3 particles as the catalyst was performed using a magnetically fluidized bed (MFB). X-ray diffraction (XRD) spectroscopy and Brunauer–Emmett–Teller (BET) method were used to analyze Fe 2 O 3 catalyst. Important effects of magnetic fields were observed in the SCR of NO by ammonia over Fe 2 O 3 catalyst. The apparent activation energies of SCR were reduced by external magnetic fields, and the SCR activity of Fe 2 O 3 catalyst was improved with the magnetic fields at low temperatures. Thus the scope of temperature with high efficiency of NO removal was extended from 493–523 K to 453–523 K by magnetic fields. Magnetic fields of 0.01–0.015 T were suggested for NO removal on Fe 2 O 3 catalyst with MFB. The results suggested that the magnetoadsorption of NO onto Fe 2 O 3 surface together with NH 2 and NO free radicals effects induced by the external magnetic fields both acted to improve the rate of SCR of NO on Fe 2 O 3 catalyst. On the other hand, magnetic field effects were also attributed to improved gas–solid contact in MFB.