Induction heating (IH) electromagnetic field has a significant positive effect on the uniform temperature distribution in tundishes and decreases molten steel superheat to improve the quality of billets in continuous casting. To achieve the effect of electromagnetic force and Joule heating for molten steel in a channel-type IH tundish, a magnetohydrodynamic model is developed and validated by industrial experiment data. The molten steel in the tundish channel has a rotating velocity under the off-centre electromagnetic force. Its flow pattern consists of two contra-rotating vortices close to the outlet zone of the channels. The upper and lower vortices in the tundish channel change with time. The temperature distribution in the cross-sections is almost stable, and the maximum temperature increases by 30.1°C. Molten steel runs upward after flowing past the tundish channel, whose density decreases because of IH. The upward motion changes when the electromagnetic force acts on the molten steel. Results reveal that electromagnetic force has a significant effect on the flow of molten steel in the tundish, and that flow pattern varies in the tundish with or without electromagnetic force under Joule heating.