The increasing importance of the sustainability challenge in ocean engineering has led to the development of floating structure of various configurations. In this study, a numerical wave tank based on the Navier-Stokes equations has been established. The turbulence model, namely standard k-ε is incorporated to the numerical tank to broaden applicability of simulation. The VOF method has been widely used in the free-surface hydrodynamic flows with good accuracy. The wave impact phenomenon is extremely complicated and restriction of experimental condition. To better understand the mechanisms and rules of wave slamming on the floating structure, in the first instance, this study simplifies the problem and assumes 5 key gestures for floating structure with inclined angles (10°, 5°, 0°, -5° and -10°) and secondly, a periodic motion deck model has been established. The computation result is in good agreement with the experimental data. The numerical method can predict the impact peak pressure and the distribution of wave impact along underside of the inclined deck. It is also significant to research the wave impact force of the inclined deck and has great scientific value and practical significance.