A mathematical model which describes the fluid flow in a gas stirred original ladle and CAS-OB ladle was introduced.The fluid field analysis was obtained through mathematical simulation.In order to decrease the ladle refractory wearing and increase the heating speed of liquid steel,some measures should be adopted.The result shows that the flow fields in CASOB ladle and original ladle are different.With a fixed gas flow rate,the flow field is related to the plug position and the snorkel depth.When the nozzle is located at 0.45 r,where r is the radius of ladle bottom,the fluid field predicted by water modeling is quite satisfactory for improving the quality of liquid steel. A mathematical model which describes the fluid flow in a gas stirred original ladle and CAS-OB ladle was introduced. The fluid field analysis was obtained through mathematical simulation. In order to decrease the ladle refractory wearing and increase the heating speed of liquid steel, some measures should be adopted.The result shows that the flow fields in CASOB ladle and original ladle are different.With a fixed gas flow rate, the flow field is related to the plug position and the snorkel depth.When the nozzle is located at 0.45 r , where r is the radius of ladle bottom, the fluid field predicted by water modeling is quite satisfactory for improving the quality of liquid steel.