Abstract: Mixing is important and critical for most microfluidics devices. An active mixing method based on magneto hydrodynamic theory is studied for microchannel flow mixing control.A mixing chamber is used for the microchannel flow mixing.The dynamic Lorentz force acted on the fluids causes them to move back and forth periodically in the chamber.The periodically changed velocity causes the interface between fluids folded and the interfacial areas increase.The repeat movement and the folding of the interface make the fluids mixed. Rapidly mixing process is recorded and the mixing performance is evaluated.