Abstract: Based on the tundish in Xingcheng Special Steel, according to the similar principle, the water modeling system of the four-strand caster tundish was built. The simulating study shows that a large difference in flow characteristics exits between the two outlets at the same side of the tunish comparing with those of the former configuration. Compared to the inside outlet, the outside outlet has short minimum residence time and peak concentration time and larger dead zone volume. So the original design of the tundish can not meet the technical requirements for inclusion floatation and temperature homogenization. With the optimal tunish configuration by using dam and weir, the RTD curves of two outlets at the same side tend to be the same, showing that the flow characteristics between the two outlets are almost uniform. With the optimal tunish configuration, the average percentage of dead zone volume is decreased to 10.9% from 58.2%.