Abstract: A kind of ceramic honeycomb support was installed in internal airlift loop reactor to form a biofilm reactor,and it was also used for study on NH₃-N removal in simulation municipal wastewater compared with the method of activated sludge.The experimental results show that the nitrification of the wastewater was increased as biofilm on ceramic honeycomb support.Compared with activated sludge,the biofilm has obvious advantage,on based which the NH₃-N removal mechanism of was discussed also.