Abstract: It is difficult for effluent from municipal sewage plants to meet the water quality standard during icy periods in winter months.To resolve this problem,based on the characteristics of high treatment efficiency and anti-impulsion load of the moving-bed biofilm reactor (MBBR),Anoxic-Oxic MBBR was used to treat sewage at low temperatures.The treatment efficiency of Anoxic-Oxic MBBR and the influencing factors were investigated under low temperature conditions.The experimental results showed that the removal efficiencies of COD_Cr and NH₄⁺-N could reach 88.70% and 65.72% respectively under the following conditions:sewage temperature 8 ℃,filling ratio of suspended carriers in the oxic MBBR reactor 40%,hydraulic retention time (HRT)　6 h and DO mass concentration 7-8 mg/L.When the filling ratio of suspended carriers in the anoxic reactor was 50% and the inner-circulating ratio was 200%,the removal efficiency of TN could reach 65.65%,and the removal efficiencies of COD_Cr and NH₄⁺-N in Anoxic-Oxic MBBR could be 90.70% and 71.65% respectively.In the test,the removal efficiencies of COD_Cr and NH₄⁺-N in the sewage showed obvious declines when the temperature in the MBBR was changed from normal to low,but they could be improved by regulating factors such as the filling ratio of carriers,DO mass concentration,hydraulic retention time,etc.in the reactor to ensure better removal efficiencies of COD_Cr and NH₄⁺-N.