This paper focuses on the detailed investigations of the (multi-) liquid flow behaviors on an inclined stainless steel plate in simulations and experiments. Simulations are carried out with FLUENT 6.3; a three-dimensional computational fluid dynamics model considering the gravity, surface tension, and local drag force is developed and presented. Experimental data is obtained with optical methods. One main aspect of the paper's presentation is the validation of the developed model for the case of one-liquid phase with a countercurrent gas phase, where the parameters (e.g., the thickness and the velocity profile of the liquid phase) are compared with the simulation results and the experimental data. The other key part of the presentation is the numerical investigations with the developed model for the case of two immiscible liquid phases with a countercurrent gas phase. Results show that with the current gas flow rate, the complex flow behavior strongly depends on the (multi-) liquid flow rates and the feed sequence. Furthermore, there is a high stability between the two liquids. All of these data lead to a better understanding of the complex fluid dynamics in three-phase distillation processes.