The arc slag retaining wall in tundish at Xingsteel is optimized and the process of double slag retaining walls is introduced. The numerical simulation of the double slag retaining walls in tundish is carried out before use

and it is found that the double slag retaining walls are beneficial to control inclusions. The production data of 148 heats with using double slag walls in tundish show that the max rating of B inclusions deceases from 3. 0 to 0. 5 ；that of D inclusions decreases from 1.5 to 0.5 ；and that of Ds inclusion decreases from 3. 0 to 0. 5 ； the unqualified rate of inclusion decreases from 7.67% to 0.