Abstract: T Steel/slag interfacial behavior in a stainless steel slab continuous casting mold was numerically simulated on the base of a coupled model of turbulence and multiphase fluid flow and the VOF method. The results of numerical simulation were validated by a water model. The steel/slag interracial profile and the behavior of steel and slag in the interface were obtained. By analyzing the influence of port form, port angle, SEN depth, mold width and casting speed on steel/slag interfacial behavior, it was pointed that slag entrapment was inherently influenced by steel/slag interracial behavior and the forming mechanism of interracial profiles and slag entrapment was discussed.