Abstract: To study the flowing process of molten steel in centrifugal tundish, the LES (Large Eddy Simulation) is used to investigate the structure of flow field in three cases, i.e., (a) tapping through a straight stopper nozzle by electromagnetic force; (b) tapping through a curved stopper nozzle by the gravitational potential of molten steel; (c) tapping through curved stopper nozzle by electromagnetic force, in this way, the process parameters due to flow structure in tundish and eddy intensity are both affected by the co-action of electromagnetic force and stopper nozzle. The results show that LES can simulate successfully the 3-D turbulent flow field in centrifugal tundish. In comparison with the tapping depending singly on either electromagnetic force or curved stopper nozzle, the co-action of rotary electromagnetic force and curved stopper nozzle can enhance significantly the horizontal eddy intensity. It is revealed that changing the straight stopper nozzle to a curved one can increase the whirling speed byl5%-19% in flow field if the electromagnetic force remains unchanged.