The so-called Goto's model was modified by introducing a parameter of the oxygen efficiency from industrial trials, as well as the selected and newly re-assessed thermodynamic data. The application of the model to copper converters in Guixi Smelter has been carried out by the combination of thermodynamic calculations with the mass and heat balance using the plant data obtained in industrial trials for many heats. For the slag-making stage, good agreements have been reached between the calculated and measured temperature, blowing time as well as the contents for main elements in the matte and the slag. Relatively large deviations for contents of Zn and Pb in the slag may be caused by the complex chemical composition of the real molten slag, which may result in a large difference of γ_zn. and γ_Pb,adopted with their real values. It is noted that the model can simulate the slag-making stage of copper converting process in industrial Pierce-Smith converters well.