Microfiltration is a popular technology in soy sauce and other brewing products clarification proceducer. As the complex components and the strict requirements in nutrition and flavor, membrane fouling is an intractable problem and the fouling mechanism hasn’t been clarified. In this work, membrane fouling mechanisms was systematically investigated by fitting the flux curve to Hermia model. Results: At the initial stage of soy sauce clarification, the fouling mechanisms was dominated by multi-mechanism, for the complete pore blocking, intermidate pore blocking, and cake layer formation model. During the following process cake layer formation predominated the membrane fouling.The influences of operating conditions to membrane fouling were further studied Results showed that when crossflow velocity increase from 0.06 m/s to 0.30 m/s, the value cake layer formation mechanism constant decreased from 6.03×10⁸ s/m2 to 6.28×10⁷ s/m2. This research provided theoretical basis in reducing membrane fouling and optimize membrane cleaning procedure.