Abstract: A micro-mixing method is proposed, by which a secondary flow is produced under electromagnetic forces. Then the Dean eddies appear to produce reciprocation flows in the micro channel. The interface of thefluids is bent and stretched. The efficiency of mixing is greatly improved due to a great increase of the contact area between two mixing fluids. The structures of three cases are discussed. A theoretical model of the micro-mixing is built and numerical simulations are carried out. The fluid mixing process is analyzed and the mixing efficiency is evaluated. Experiments are carried for verification.