According to the flocculation kinetics theory, micro-vortex scale was introduced to analyze the state of flow field in integrated flocculation-membrane filtration process. Combining numerical simulation with experimental investigation based on real-time image analysis, it was investigated that the characteristics of flow field in various reactor configurations and flocculation operational parameters. For numerical simulation, the results reveal that the best operational performance of integrated process can be achieved in the configuration of partial flocculation (PF) which occurs in the tank with a partition settled between flocculation area and membrane filtration area. When volume ratio of flocculation unit and membrane filtration unit is 2 to 1, which also means that the retention time of flocculation unit lasts longer than that of membrane filtration unit, in this work 27 min and 13 min respectively, Combining numerical simulation with experimental flocs of which size is similar to micro-scale vortex form larger-size ones that benefit forming loose cake layer through relative motion and collision, which can mitigate membrane fouling. (C) 2014 Elsevier B.V. All rights reserved.