Abstract: Facing upon the membrane fouling in a membrane bioreactor,a novel aeration and filtration unit was developed,aiming at effectively enhancing flux as one factor and considerably providing the oxygen in the need of microorganism as the other one.The characteristics of filtration flux were studied by terms of tap water,kaolin solution and activated sludge.The quality of high flux with tap water and kaolin solution was obtained,and the reason of no high flux with activated sludge was analyzed.Optimum operation parameters of Unit 2 were determined in the experiment of kaolin solution:the pressure,0.15 MPa;the rate of surface scouring,9.26 m/s;the intensity of aeration,18 m³/(h·m²);the operation time,70 min;the aeration time,5 min.The comparison of aeration influence on filtration flux tentatively showed that air backwash was a remarkable way to enhance filtration flux.