In engineering applications,for the revetment engineering under the wave action,the surface layer-filer layer-subsoil design patterns are usually used for the slope protection with a filter layer structure as the cushion;but in the practical project,the cushion structure is often simplified,with the geotextiles directly laid on the sand. Based on the theoretical analysis and model test,we study the impact of the cushion structure under the wave action,and comes to the conclusion that when the top layer’s permeability coefficient is less than that of the filer layer,the uplift force acting on the top layer will be generated inside the filer layer,which may lead to the instability of top layer. The results may serve as reference for the similar engineering.