The performances and membrane fouling of the spiral symmetry stream anaerobic membrane bioreactor (SSS-AnMBR) during stable operation period with and without biogas aeration were studied. The organic loading rate (OLR) and chemical oxygen demand (COD) removal rate of the SSS-AnMBR with aeration biogas condition were 2.28 kgCOD/(m(3) d) and 98.24%, respectively, higher than those without biogas aeration (2.13 kgCOD/(m(3) d) and 97.58%, respectively). Biogas aeration could reduce effectively membrane fouling, and the service time of the membrane was twice as much as without biogas aeration. Without biogas aeration, the main causes of membrane fouling were high total solids, volatile suspended solids and total extracellular polymeric substances (EPS) on the membrane surface; with biogas aeration, the main causes of membrane fouling were high slime-EPS, polysaccharide (PS) and small value of PN/PS on the membrane surface.