Abstract: To address the issues of flow field turbulence and unstable steel-slag interface in the thin slab continuous casting mold under high casting speed conditions,this study takes the FTSC thin slab mold and full-width singlesegment electromagnetic braking（Ruler-EMBr）system of a steel plant as the research objects.A coupled model of Large Eddy Simulation（LES）and Volume of Fluid（VOF）is adopted for numerical simulation,with a focus on analyzing the influence law of different magnetic flux densities on the flow characteristics in the mold when the casting speed is 6.0 m/min.The results show that electromagnetic braking can effectively regulate the flow field in the mold,improve the stability of the steel-slag interface,and prevent the abnormal rise of the steel-slag interface.When the Ruler-EMBr system is applied with a magnetic flux density of 0.23T,the maximum velocity of the steelslag interface is controlled within 0.30m/s,the maximum wave height is limited to 10 mm,the fluctuation range of the interface position is maintained within±2 mm,and the turbulent kinetic energy of the steel-slag interface is suppressed below 0.045J/kg.These findings fully verify the flow field regulation effect of the Ruler-EMBr system.