According to tundish for thin slab caster in a steel factory, 1:3 water modeling and numerical simulation were established. By measuring RTD(Residence time distribution) curves of fluid flow in tundish, real residence time, plug flow volume fraction and dead zone fraction were computed, influence of turbulence controller structure on flow mode of molten steel in tundish were studied. The results show that fluid flow in tundish can be improved, if turbulence controller has reasonable structure. A reasonable turbulence controller structure was obtained. Water modeling results agree with numerical computing results well.