In this paper silicon ingots were continuously and directionally solidified by electromagnetic casting (EMC). A group of orthogonal experiments were completed to investigate the effects of input power, withdrawal velocity and initial heat preservation time on the grain growth of silicon ingots. The results showed that all of the deviating angle (theta), the convex height of the solid/liquid (S/L) interface, the thickness of the surface fine grain zone and grain size in the centre zone decrease with increasing input power and withdrawal velocity. Increasing initial heat preservation time results in larger grain size in the centre zone, but has little effect on the convex height of S/L interface and the thickness of the surface fine grain zone. The results were explained by the heat transfer analysis during the steady casting process and the optimised parameters for casting silicon were given finally. (C) 2011 Elsevier B.V. All rights reserved.