This paper presents a novel dielectrophoresis (DEP)-based microfluidic device which combines round hurdle with an S-shaped curved microchannel for continuous manipulation and separation of microparticles. Local nonuniform electric fields are generated by means of both constricted gaps and curved sections having equal width. Under the effect of negative DEP, particles transporting throughout the microchannel electrokinetically will be directed away from either inner wall or hurdle edge. Both experiment and numerical simulation were conducted, the results of which showed that the trajectories of fix-sized (i.e. 10 or 15 μm) polystyrene (PS) particles could be controlled by adjusting applied voltage, and continuous size-based separation of 10 and 15 μm particles was achieved. Compared to other microchannel designs that make use of either obstacle or curvature individually for electric field gradient, the developed microchannel offers advantages such as improved controllability over particle motion, lower requirement of applied voltage, reduced fouling and particle adhesion, etc. © 2013 AIP Publishing LLC.