Abstract: The membrane separation sewage purifier is suitable for the treatment of the sewage of small town.The membrane separation sewage purifier was adopted to treat dispersed domestic sewage in small towns.The removal effect of the purifier on COD,NH₃-N and TP in domestic sewage was monitored,as well as the possibility of the purifier in small urban domestic sewage.It was found that membrane separation sewage purifier could effectively remove COD,NH₃-N and TP,and occupied less area per ton of water,which indicated a certain value of practical promotion and application promotion.