The present invention relates to a membrane separation method and a relevant equipment, in particular to a method and an equipment for membrane separation utilizing concentration polarization during membrane filtration process, especially, to a concentration process and equipment and a drawer special for drawing a concentration polarization layer. The direct removal of the concentration polarization layer from membrane surface not only decreases the adverse influence of concentration polarization on membrane separation but also obtains concentrated retention components, thereby significantly improving the ability to maintain membrane flux, solving the twinborn problems concerning concentration polarization and membrane fouling during the membrane separation process, and achieving a high-efficiency concentration for retention components. The method and equipment of the present invention can be widely applied in various membrane techniques, in particular in a membrane separation process for concentrating biomacromolecule and organic micromolecule products such as sugars, organic acids and polypeptides etc.