MBR is the latest waste water recycling technique that combines ASP with Microfiltration membrane. Microfiltration separation replaces traditional secondary sedimentation tank to achieve the separation of HRT and STR. It functions well against sludge expansion so that active sludge concentration can reach 10000～20000g/l which micro-organisms degrading the organics is enhanced. MBR has high shock resistance and stable permeability and high permeate quality which micro-organism and suspended solids is almost zero. It is strongly recommended being process for recycling waste water.