Abstract: A numerical model was established to simulate the flow field in a Peirce-Smith converter bath, which is extensively adopted in copper making. The mean phase and velocity distribution, circular area, and mean wall shear stress were calculated to determine the optimal operation parameter of the converter. The results showed that the slag phase gathered substantially in the dead zone. The circular flow was promoted by increasing the gas flow rate, Q, and decreasing the nozzle height, h. However, these operations significantly aggravate the wall shear stress. Reducing the nozzle diameter, d, increases the injection velocity, which may accelerate the flow field. However, when the nozzle diameter has an interval design, the bubble behaviors cannot be combined, thus, weakening the injection efficiency. Considering the balance between the circular flow and wall shear stress in this model, the optimal operation parameters were Q=30000-35000 m³/h, h=425-525 mm, and d=40 & 50 mm.