Abstract: Based on the metal elements contained in crude zinc, the evaporation kinetic experiments of the Cd-Zn, Bi-Zn and Bi-Sn-Zn systems in vacuum distillation were carried out. The Langmuir formula was used for theoretical prediction of evaporation rate. The results are in good agreement with the experimental data. It indicates that the method of evaporation rate calculation is applicable. The condensation coefficients of zinc in the alloys were calculated. The relationship between the interaction and the evaporation rate of components in the alloys was discussed. It will be helpful to the separation and purification of crude zinc and the optimization of experimental equipmentby vacuum distillation.