Abstract: It was found that the mold with hot top was unsuitable for magnesium ingots in the DC low-frequency electromagnetic casting (LFEC) process, because of the high reactivity between hot top and magnesium melt which will affect greatly the productivity and quality of the billets. The effects of the electromagnetic (EM) parameters on the EM distribution and how they affect the magnesium melt were investigated by numerical simulation with a metal bushing attached to the mold. The results indicated that EM frequency affects not only the magnitude of Lorentz force but also its direction. In the low-frequency EM field, the long penetration depth, low Joule heat, weak magnetic confinement, strong convection and shallow melt trap can all be achieved. When the excitation coil is held at high level, the EM penetration becomes deeper with the melt pushed outwards more rapidly, and the Joule heat in the high-resistivity bushing becomes lower.