Continuous separation of protein mixtures by multichannel flow electrophoresis (MFE) was carried out in a 5-compartment electrolyzer partitioned by membranes. Polyvinyl alcohol(PVA), polyethylene glycol 4000(PEG 4000) and polyvinylpyrrolidene K30(PVP K30) were applied to the MFE as shielding polymers to prevent protein adsorption on the polyethersulfone microfiltration membrane, which was used to space the central compartment and the elution compartments, during the electrophoresis process. The effects of polymer concentration on protein transmembrane flux were examined. It was found that PVA, PEG 4000 and PVP K30 greatly reduced protein adsorpton on the membrane surface. Continuous separations of bovine serum albumin(BSA) and hemoglobin(HBB) mixture in the presence of PEG 4000 yielded 26.6mg BSA 40.4mg HBB per hour. These results have shown a high potential of scaling up MFE for large scale separation and purification of biomolecules.