Abstract: As a promising wastewater treatment technology, the membrane bioreactor (MBR) has higher demand in carbon-nitrogen ratio than the conventional biological treatment during denitrification, and the dissolved oxygen and carbon-nitrogen ratio are the important factors to the total nitrogen removal of MBR. Based on the conventional membrane bioreactor (CMBR), a modified hybrid membrane bioreactor (HMBR) was designed by combining with other technologies. The performance of modified HMBR and CMBR during long-term operation was compared. The results showed that although HMBR and CMBR manifested almost the same efficacies for COD_Cr and NH₄⁺-N removals, HMBR could improve the TN removal efficiency, which was averagely 7.1% higher than that of CMBR, and shortened the start-up period, strengthened capabilities of shock loading resistance and showed faster speed of recovering normal. The biofilm surface of the BF had better nitrification ability and dehydrogenase activity than suspended sludge and bore half weight of total biomass of HMBR system. Under the disturbance of improper waste water, the biofilm surface of the BF showed stronger stability than suspended sludge, which enhanced the nitrogen removal ability and the stability of HMBR system. HMBR could prevent sludge bulking and slow down the pace of membrane fouling effectively and reduce about 15.3% of the extracellular polymer substances.