Abstract: A comparison between the solidification structure of Sn-4Cu alloy with and without high magnetic field had been done to investigate the influence of magnetic field on the solidification.The results show that the Cu6Sn5 crystals had grown and aligned along the magnetic field direction.The shape of Cu6Sn5 crystals at the top was different from that at the bottom in the alloy.The Cu element distribution changed from the top to the bottom remarkably.This phenomenon indicates that the high magnetic field restrains heat convection.From the XRD analysis results,it can be found that high magnetic field has slight effect on the Cu6Sn5 crystals orientations.