Abstract: Falling film evaporation plays a key role in the heat removal process of the containment of the CAP1400. In order to estimate the heat removal capability of the containment, it is important to calculate the evaporation rate accurately. In the paper, two different evaporation models were built to simulate film evaporation in a vertical channel based on ANSYS FLUENT code. The prediction results by two evaporation models and experimental data were compared. The results show that both models can predict the evaporation heat transfer coefficient accurately. The results calculated by the model 1 are more reliable with finer mesh. The model 2 can be used with coarser mesh near the wall. However, the model depends greatly on the calculation of the convective heat transfer coefficient.