Electroslag remelting process can improve the quality of the ingot for special usage. Complex physical phenomena are involved in this process and the influence of the magnetic fluid flow, the heat and mass transfer, as well as the electrochemistry must be taken into account. By coupling the electromagnetic field, the flow field and the temperature field, a three-dimensional transient-state mathematical model has been developed to analyze the influence of melting rate on electroslag remelting process. The simulation results show that, with the increase of melting rate, the current density, joule heat and electromagnetic force become bigger, and the maximum value of field increases more than 100% when melting rate increases from 14.4 kg/h to 27.0 kg/h. With the increase of melting rate, the maximum value of temperature increases a little, while the maximum value of velocity increases about 50%, and the depth of metal melting pool increases from 27 mm to 38 mm, which is harmful to the ingot quality.