This study investigated the role of initial molten pool on the numerical simulation to melting process. The critical time for heat conduction mechanism to control the formation of initial molten pool is estimated first. A realistic formulation to the initial molten pool is then proposed. The linear stability characteristics of the initial molten pool when subject to Marangoni flow induced by the perturbations of surface liquid temperature were also analyzed. For initial pool having a melting time less than the critical time, the subsequent numerical results are independent of the assumed initial pool. An arbitrarily assumed initial pool could yield erroneous numerical results for melting. Detailed numerical investigations on the shape evolutions of molten pool during initial stage and the long-term stage were conducted. Effects of the heat transfer intensity and the Marangoni number on the melting process were also investigated. (C) 2000 Elsevier Science Ltd. All rights reserved.