Abstract: In order to optimize the flow pattern of molten steel in the continuous casting tundish to effectively remove nonmetallic inclusions，a multi-hole flow control device with different apertures was proposed in this study.A 1∶4 hydraulics model experiment was conducted to simulate a 70 t two-strand slab continuous casting tundish to measure RTD curves and a three-dimensional numerical model was established to analyze the flow field. The effects of the casting speed and the installation position of the flow control device on the flow characteristics of the molten steel in the tundish were studied，and the optimal combination of flow control devices was obtained. The results show that the flow rate is improved, the path of the fluid flow can be prolonged, the average resistance time is prolonged and the dead zone volume fraction is decreased. The flow control device of S_f=4 has the best effect on improving the flow field when the distance between the flow control device and the weir is 150 mm, and when the casting speed is 1.0，1.2，1.4 m/min，the dead zone volume fraction decreases 17.42 %, 15.55 %，28.72 %，the peak time is prolonged by 75, 41，56 s, the average residence time is prolonged by 78, 87, 126 s, respectively. 

Key words: tundish, flow control device, fluid field