Abstract: In view of excessive non-metallic inclusion content in a three-strand tundish for 320 mm×480 mm bloom casting,the effect of flow control device on flow characteristics of the tundish has been studied by water modeling with a geometrical similarity ratio 1:2 to optimize the tundish flow field.The results reveal the problems with the prototype tundish such as short residence time,large dead zone and erosion in the front wall of tundish by continuous flow of molten steel.The residence time is increased by 18.05 s while standard deviation of residence time S_tmin between the two nozzles is only at 0.18 and the dead zone is decreased by 30.15% by using the baffle and dam in scheme 3,which greatly improves the flow characteristic of liquid.