In order to study the specialties of wave slamming on open-piled structures, two-dimensional regular wave numerical models were established based on the software FLUENT. RANS equations were adopted.The standard k-ε equations were used to close the Reynolds equations. VOF method was used to reconstruct the free surface. Through three typical cases of wave slamming on open-piled structures were reproduced, the models were verified by experimental data and the average of peak impact pressure was chosen as the characteristic impact pressure.Then with plentiful simulation the parametric studies had been carried out for different wave steepness, structure geometry and the distance between underside of structure and still water level. Good agreements between the numerical and experimental results were obtained.