A sequencing batch biofilm filter was a novel technology based on SBBR. As the sequencing batch biofilm filter was not efficient for phosphorus removal in the treatment of domestic sewage, FeSO₄ 7H₂O was added to the SBBF in order to achieve chemical aided biological phosphorus removal, which was meaningful for nitrogen and phosphorus removal in wastewater treatment. When concentrations of Fe(Ⅱ)varied from 0.03 to 0.3 mM, it indicated that 0.2 mM Fe(Ⅱ) might be a proper dosage. When 0.2 mM Fe(Ⅱ)was added to the bioreactor at the end of influent phase for one month, the effluent TP remained stable at below 0.5 mg/L, and the removal of COD and nitrogen were not affected. The average removal efficiencies of COD、NH₄⁺-N、TN and TP were 84.9%、83.2%、46.3% and 88.2%, respectively. The parameters of reactor effluent were stable to achieve the A standard "discharge standard of pollutants for municipal wastewater treatment plant (GB 18918-2002)".