Abstract: The calculated fluid dynamics (CFD) model of the two-phase flow field in the directed trapezoid spray tray（CTST-8）was established with the volume of fluid（VOF）method. The physical model was established with the software Gambit，and the grid was adapted by the gradient of velocity. Under the condition that the gas velocity in the tray hole was kept at 8. 4 m·s-1 and clear liquid height was kept at 25 mm，calculation was carried out with commercial software FLUENT 6. 1. The results showed the three-dimensional characteristics，and displayed the detailed information of the flow field in the cover such as the distribution of phase volume fraction，velocity field，and pressure field. The pressure values in the cover and the relative liquid-liftup of a single-cover acquired by the simulation were in good agreement with the experimental results. The model had a high degree of accuracy，and could be used to predict the two-phase flow field in CTST-8.