The influence of effluent discharging modes on membrane fouling in a submerged membrane bioreactor was evaluated, and the feasibility of the characterization of membrane fouling using Flundlich isothermal adsorption equation was also explored in this paper. Under the same operation conditions, the adsorption equations of three discharging modes of vacuum pump drawing combined with air back-blowing, vacuum pump drawing and suck pump drawing were 2.59ce1/0.957, 7.415ce1/1.369 and 7.10ce1/1.015. Experiment results showed that the effluent-discharging mode had a significant influence on membrane fouling in the submerged membrane bioreactor. Among three discharging modes, the membrane fouling degree in the mode of vacuum pump drawing combined with air back-blowing was the lightest. The experimental results also indicated that Flundlich isothermal adsorption equation is applicable in the characterization of membrane fouling.