Based on Euler-Euler approach, a mathematical model is established to describe gas and liquid twophase flow in the mechanical-gas injection coupled stirred system for steelmaking, and the effects of different location and rotation speed of impeller, and gas flow rate on the bubble dispersion, gas total volume and mixing time in the bath were studied. The results show that the predicted bubbles dispersion and mixing time agree well with the experimental photos and measured data. With the increasing of impeller eccentricity, the bubbles dispersion become more better, and the mixing time decreases, while the gas total volume first decreases and then increases. With the increasing of rotation speed of impeller, the bubble dispersion becomes better, and the gas total volume the mixing efficiency also increases. But these effects become weak when the rotation speed exceed 200 rpm. With the increasing of gas flow rate, the bubble dispersion remain basically unchanged, and the gas total volume gradually increase, but the mixing time would rapidly increase. It is recommended to use the impeller placed at radial position of 0.4 R (R is the radius of bath), rotation speed of 200 rpm, and gas flow rate not exceeding 2.0 Nm 3 /h for present system.