Abstract: The blowing hole location and the gas flow in a 150 t elliptic ladle were optimized by establishing a 1:4 water model.Based on the similarity criterion,high pressure nitrogen was used to simulate argon in the water modelling experiment. Experimental results show that the mixing of liquid steel is weak in the original ladle because the two blowing holes are close to each other. A critical gas flow exists at different locations. Beyond the critical value,the increase in kinetic energy mainly is used to stir liquid steel and blow the slag surface. After optimization,the two blowing holes distribute in 180° and are arranged at the 0.6 radius of the major axis respectively. The mixing time of liquid steel shortens and the exposed area of liquid steel reduces greatly compared with the original ladle with the same gas flow. Moreover,the total oxygen decreases to 47×10^-6 from 58×10^-6 during calcium treatment,and the average nitrogen pick-up amount is less than 3×10^-6 during the soft stirring process.