A method for attenuating laser power density employing the reflection characteristics of material is studied. By using the classical Phong reflection model, the reflection characteristics of material are theoretically analyzed, and the function describing the relation among power, radiant intensity and observation angle is presented under continuous-wave (CW) laser irradiation. By selecting appropriate parameters of material for the Phong reflection model, the numerical simulation results for the structure for attenuating laser power density are given, such as the three-dimensional (3D) laser beam spatial profile of the structure at the output and the attenuation coefficient at different distance from the output. They are consistent with the experimental results. The research results demonstrate that the structure is suitable for attenuating laser power density and quantitatively measuring laser parameters.