Abstract: The second-phase segregation is highly liable to occur in the solidification process of Zn-Bi hypermonotectic alloy, because of the liquid-liquid separation reaction. The magnetic field can suppress the migration of second-phase droplets in the solidification process. An experiment was done for casting the Zn-Bi hypermonotectic alloy into water-cooled copper mould in a horizontal steady magnetic field, to investigate the effect of magnetic field on the solidified structure of the alloy, where the moving direction of second-phase droplets in each part of the sample have a different angle with the magnetic field. The results showed that the magnetic field can suppress the Marangoni motion of Bi-rich phase, and the magnetic field has most obvious effect when its direction is parallel to the Marangoni motion of Bi-rich droplets.