Abstract: The separation coefficient of carbon isotopes is small, high-efficiency structured packing should be used in the separation of ¹³C. So the self-developed high-efficiency structured packing PACK-¹³C was put forward. By means of computational fluid dynamics (CFD), a local falling film flow of mesh corrugated packing PACK-¹³C with the gas phase counter-current model using the volume of fluid (VOF) was presented. CO(l)-CO(g) was selected to be the simulation mixtures. Based on the simulated results, the influences of the plate structures and the mesh sizes on the film flow were investigated. Based on the gas-liquid interface tracking timely, the influence of interface fluctuation on the mass transfer efficiency was also investigated. The results showed that improving the wall structures to enhance the interface fluctuation was the effective way to strengthen the mass-transfer efficiency. The method of local falling film flow study could be applied to research the multi-scale flow and mass-transfer behavior of the packing which provide some theoretical guidance about the optimization of the packing’s structures.