Based on the direct simulation Monte Carlo (DSMC) method, one- and two-dimensional models of vapor flows in the short path distillation are established. To reflect the reality, molecular rotation is included in this study and a reasonable boundary condition is introduced. The simulations are tested by comparison with the previous experiment, which shows that the distillation rate and composition are closer to the experiment compared to the previous models, and the simulated temperature field is higher than that of the previous models. The agreements between experimental and simulated results show that the models represent well the phenomena that occur in the vapor space of the short path distillatory. Based on the revised model, macroscopic variables related to a particular position in the distillation gap are analyzed in detailed. Furthermore, dependence of the evaporation efficiency on the ratio of condensing area to evaporating area and influence of inert gas on the distillation process are investigated. (C) 2012 Elsevier Ltd. All rights reserved.