A mathematical model based on the Euler-Euler-Lagrangian approach has been developed to study the influence of argon gas injection on the molten steel flow and particle transport behaviors in continuous casting mold. The modified k-ε model with extra source term to account for the bubble-induced turbulence is adopted to model the turbulence in this system. The transport of particle is simulated using a Lagrangian approach based on the computed two-phase flow fields. A 1/4th scale water model has been developed to investigate the bubble behavior and fluid flow pattern. Air is injected into the submerged entry nozzle (SEN) through a circumferential inlet chamber which is made using specially-coated samples of mullite porous brick. The predictions of gas bubble distribution and fluid flow pattern are in good agreement with the water model experimental observations. Argon bubbles can change the flow pattern in the upper recirculation zone of the mold, increase the fluctuation of the top surface, and shift the impingement point on the narrow wall. The effect increases with increasing argon gas flow rate, and decreasing casting speed and bubble size. Argon gas injection enhances the removal of particles. The optimum argon gas flow rate between 5 and 10 L/min, casting speed between 0.7 and 0.8 m/min, and argon bubble size around 2.5 mm are obtained using this model to improve the removal of particles.