Abstract: Optimization of flow field in the mold is an important approach to controlling inclusions and stabilizing slab quality in steel production. A rational flow field of molten steel in the mold can effectively reduce steelmaking defects and improve the surface quality of continuous casting slabs intended for automobile outer panels. The effect of argon flow rate on the flow field in mold,surface flow velocity and fluctuation of molten steel level were studied by a method of combining numerical simulation, water modeling with high temperature velocity measurement. The results showed that the results of numerical simulation, water modeling and high temperature velocity measurement were in good agreement under the three argon flow rates; with the increase in the flow rate of argon gas,the flow velocity of molten steel near the surface of the mold decreased and the flow field was a double-recirculation flow. As the argon flow rate increased,the flow of molten steel from region near the nozzle to the narrow face became progressively unstable and evolved toward a singlerecirculation flow,accompanied by the contraction of the jet region in the mold and the reduction in scouring velocity of the narrow-face jet. When the argon flow rate was larger,the molten steel level near the nozzle fluctuated intensely with the result that slag eyes and bubble entrapment is easy to produce. It was recommended that the argon flow rate was controlled at 6 L/min during trial continuous casting.