Abstract: Though various new cathodic structures of aluminum reduction cells have been applied in industry, their electro-magneto-flow is still not completely clear. In this paper, a transient 3 D three-phase MHD model in aluminum reduction cells was established on ANSYS platform, and then was utilized to calculate the strong coupling of electro-magneto-flow in some 420 kA cells with three kinds of new cathodic structures. The results show that compared with common cathode, three new cathodic schemes can decrease the flow rate of aluminum liquid and electrolyte in the cells. The flow rate of electrolyte in the case of boss-type cathode declines significantly, which is not conducive to the melting and dispersion of alumina particle. In the reduction of aluminum liquid and electrolyte interface fluctuation, the above-mentioned three schemes all have certain effects. The boss-type structure can reduce the interfacial regions with large deformation. In addition, such structure will slightly decrease current efficiency. This model can provide a basic tool for choosing structure scheme of large aluminum reduction cells.