The effect of liquid multiphase parallel flow stabilizing method (i.e. guideline structure addition and surface modification) was studied in a curved microchannel by using CFD simulation. A phase separator function can be combined within a microchannel by operating under stable parallel flow conditions. Based on our simulation conditions, the flow pattern could not be improved by using the guideline structure but the surface modification proves to be beneficial. (C) 2014 Elsevier B.V. All rights reserved.