Abstract: The multi-layer honeycomb structure has recently attracted extensive attention due to its excellent absorbing per-formance and high-strength structure. In this paper, aiming at the electromagnetic discontinuity at the interface of the traditional multi-layer honeycomb and the low precision of the impregnation process, a lightweight three-layer gradient honeycomb structure with broadband electromagnetic wave absorption capability is fabricated by 3D printing technology. Interface reflections between layers are reduced by intermediate layer with gradient wall thickness significantly. The structure achieves reflection loss below -10 dB within the frequency range of 2. 92 GHz~ 18 GHz, with a relative absorption bandwidth of 144% at -10 dB, and a density of only 0. 292 g / cm3. Simulation and experimental results demonstrate that the composite design of uniform wall thickness honeycomb and gradient wall thickness honeycomb can ensure electromagnetic continuity at the interfaces, which effectively improve the impedance matching, electromagnetic wave absorption capabilities and wide-frequency absorption.