The main factors which influence the absorbing effects of the perfectly matched layer (PML) method are the thickness of ab- sorbing layer and the attenuation coefficient. Based on the numerical simulation of the seismic wave field, the author discusses the im- pact of the thickness of absorption layer and the attenuation coefficient on the absorption effect. The results show that, under the condi- tion of constant attenuation coefficient, the larger the thickness of the absorption layer is, the weaker the boundary reflection becomes. The abso...