Abstract: The fluid flow in argon blowing ladle is driven by buoyancy of bubble. In order to quantitatively describe the fluid flow phenomena, it is essential to understand the structure of argon-liquid zone. In the present paper a numerical model was built to research the velocity field, gas fraction distribution under different quasi-single phase flow models. The classical Castillejos model was used to study the mixing behavior during teeming process in ladle. With increase of gas blowing rate, the mixing time decreased. Under same argon blowing rate, as the free surface goes down the mixing time became shorter. Nevertheless, when surface level was lower than 200mm, the variation law reversed, that is because the circulation flow became weaker at lower surface level condition. The results obtained in this paper could provide theoretical support for understanding the fluid flow and mixing behavior in ladle.