This paper analyzes the wave absorption efficiency of multi-layer perforated plates in an ideal fluid, based on the linear potential flow theory. The influence of the thickness, the porosity and the layout form of the plates on the wave absorptivity is studied on the assumption that all perforated plates are composed of the same materials and have the same thickness and porosity. The calculation results indicate that the larger the number of layers of the perforated plate set, the better the wave absorption efficiency, however, when the layer number exceeds a certain value, the efficiency of the plates is not significantly increased. For the case of porosity ε= 0.2, thickness b = 0.07 m and 4 layers of perforated plates with a distance l=1.0 m between the layers, 90％ of the energy of the wave within the incident wave period between 1.6 s and 4.4 s can be absorbed.