Abstract: On the basis of similarity theory,a physical simulation system for 85 t ladle furnace had been established to simulate ladle bottom argon blowing process.The required mixing time for various position at different flow rate had been measured in order to determine the optimal location of bottom gas permeable brick and the optimal flow rate of ladle blowing.Simulation results indicated that the prototype single blowing had not achieved as-expected effect while double blowing produced a moderate effect.The optimal position of gas permeable brick was at the position of 0.5R and the gas flux was controlled in range of 300~350 L/min for single hole blowing,while.The best position of gas permeable brick was at 0.5R,with the angle of 90°,and the best blowing gas flux controlled at 350 L/min for two holes blowing.