Abstract: To improve the output and quality of products in casting, the existing manual speed control for billet caster with molten steel level in mold controlled by stopper was investigated. A feed forward control system was thus designed according to the optimal relationship between casting speed and superheat which was obtained from the casting speed optimization control model that developed on the basis of the heat transfer model and production practice, with the restriction on maximum casting speed and shell thickness at mold exit involved. Furthermore, a hierarchical control system was designed where the casting speed changes with superheat. The reliability of changeover of the control modes switched was discussed emphatically. Field application shows that the proposed control system runs robustly and reliably and satisfies the production requirements.