The fused deposition 3D printing technology was used to print the pyramid structure. The printing material was PLA （thermoplastic plastic）， and the composite absorbing material of pyramid structure was prepared. The prepared pyramid samples were hollow structures， with a single pyramid wall thickness of 1 mm， a height of 20 mm， and a total base area of 200 mm×200 mm. The influence of the angle and height of the pyramid on the absorption performance was studied. The reflectance of the 4~18 GHz band range was measured by the bow method. Because the angular pyramid absorbing material had gradient structure， it also had many absorbing mechanisms such as dielectric loss and interference cancellation. The results show that the angular pyramid structure has excellent absorbing performance. The absorbing performance of the angular pyramid structure increases with the decrease of the angular cone angle （33°~73°）. Different angular pyramid structure parameters have different effects on the absorbing performance at C， X and Ku bands.