Abstract Ti3C2TX MXene has been proven to be a material of high application potential in the field of electromagnetic (EM) protection. Considering the density, MXene/polymer films (MPFs) are fabricated by employing the simple tape casting process and exhibit excellent electromagnetic shielding performance with respect to the MXene content. However, the absorption properties of as-fabricated MPFs are not satisfactory due to the impedance mismatch. Herein, a multilayer impedance gradient absorber with MPFs arranged in order has been successfully designed and prepared. The developed absorber possesses excellent EM wave absorption properties owing to the well-matched impedance and adjustment of permittivity. Moreover, the effect of the thickness of MPFs on the EM wave absorbing properties has been investigated by theoretical calculations and experimental measurements. The HFSS calculation reveals that the effective absorption bandwidth is capable to cover the whole X-band (8.2–12.4 GHz) with only a micro-adjustment of the thickness, with the minimum reflection coefficient (RCmin) reaching up to −26.10 dB. In addition, the synergistic effect of the multiple loss mechanisms has been discussed in detail. This study not only proposes the effective design of a novel multilayer impedance gradient absorber, but also provides new fundamental basis for combining the simulation technology and material design.