Abstract: For the three-flow asymmetric tundish, ANSYS Fluent software was used to simulate its flow control scheme. The flow field, temperature distribution and residence time distribution (RTD) characteristics of molten steel under different scenarios were compared. The simulation results show that there are obvious short-circuit currents in the original scheme, and the consistency of molten steel flow at each nozzle is poor. The actual residence time of the three nozzles is 459. 44 s, 519. 43 s, and 636. 94 s respectively, and the maximum temperature difference is 7 K. The proportion is 23. 9% ; the optimal optimization scheme reduces the short-circuit flow and improves the consistency of the molten steel flow. The actual residence time of the three nozzles is 517. 13 s, 532.66 s, and 502. 12 s respectively, the dead zone ratio is reduced to 19.8% , and the maximum temperature difference is reduced to 2. 5 K, the flow consistency is good and the flow of molten steel is more reasonable. In the industrial test, the content of T[0] in the tundish was reduced from 49 x 10^-6 to 40 x 10^-6, and the decrease was 18.4%. The casting billet T[0] was reduced from 34 x 10^-6 to 28 x 10^-6, and the decrease was 17. 7%, The purity of the inclusions in the tundish was reduced from 7. 2/mm² to 4.7/mm², and the cast billet decreased from 5.4/mm² to 3. 5/mm² , and the number of inclusions decreased.