Abstract: Based on the numerical simulation,fluid flow and heat transfer of molten-steel in a curved shape six-strand tundish for the billet and roud billet caster under different conditions(bare tundish and tundish with flow control device) were analyzed.The results showed that the tundish with flow control device which make up of "V" type baffle with holes,turbulence inhibitor and dam more effectively reduce the wall shear stress on the curved wall,optimize tundish flow field,uniform temperature distribution of molten steel and promote nonmetallic inclusions removed.The investigation results of the adoption of flow control device on the six-strand tundish showed that tundish temperature difference between adjacent stream is less than 5 K,the maximum of average temperature difference is 2.7K;average T[O] of 37Mn2 is 17×10^-6;the size of oxide inclusions is less than 50μ m in the slab samples.