Abstract: Based on the principle of Gibbs energy minimization and the technological propertyof oxygen bottom blowing copper smelting process, the multiphase equilibrium model was established. The improved particle swarm optimization was applied to calculate the model. Then SKS simulation software(SKSSIM) was developed independently. A set of industrial data were compared with the predicted data. It is found that the relative errors between industrial data and predicted of Cu, S, Fe, SiO₂ contentin matte from bottom blowing copper smelting are 0.65 %, 13.04 %, 0.79 % and 39.22 %, respectively, and the relative errors of Cu, S, Fe, SiO₂ contentin smelting slag are 7.28 %, 1.20 %, 15.12 %, 0.24 %, respectively.The tri-phase (matte, slag and gas phase) distribution coefficients of arsenic are 0.062, 0.110, 0.828, of antimony are 0.125, 0.723, 0.152, of bismuth are 0.188, 0.113, 0.700, of lead are 0.567, 0.234, 0.199 and of zinc are 0.173, 0.665, 0.162, which proves the reliability of SKSSIM simulation software with important practical application value.