This study investigated issues relating to the multi-scale simulation of falling film short-path distillation. Both hydrodynamic conditions and gas phase kinetics have a considerable effect on the distillation process. At the micro-scale, the DSMC (direct simulation Monte Carlo) method was adopted. Both molecular rotation and translation have been taken into account, and we obtained the temperature distribution along the distillation gap. At the meso-scale, we used Excel as a bridge between the micro-scale and macro-scale. We obtained the evaporation efficiency for different temperatures. At the macro-scale, the evaporation efficiency was used to modify the Langmuir equation, then the modified Langmuir equation was written into the mass transfer source. We used Fluent to carry out the numerical simulation. Thus, the gas phase and liquid phase were coupled. Only considering the gas phase and neglecting any surface wave in the liquid film leads to inaccurate results; this paper makes up for past deficiencies. It is found that the evaporating temperature, condensing temperature, and distillation gap have significant effects on the temperature distribution in the gas phase. The heat and mass transfer processes are correlated with the interfacial vorticity Omega(i). To quantitatively describe the relation between the interfacial vorticity and concentration in the interface, we proposed a correlation coefficient R-Omega. It is also observed that the average value of R-Omega is 0.63, and the local maximum value of R-Omega is usually located in the region of the wave trough.