In this work, the layered Ti3C2Tx MXene were coated with polypyrrole particles by an in-situ polymerization method, and their electromagnetic wave absorption performance were systematically studied. The MXene/PPy composites presented an excellent electromagnetic wave absorption performance, the strongest reflection loss can reach − 68 dB at 2.68 mm. Meanwhile, when the thickness is 2.26 mm, the effective absorption bandwidth can reach 6.56 GHz (from 11.44 to 18 GHz), covering the entire Ku band (12–18 GHz). The multiple reflections at the heterogeneous interface, and the synergistic effect between the layered MXene and the conductive polypyrrole network made a combined effect on the optimized absorption. The MXene/PPy composites with a strong electromagnetic wave absorption, wide effective absorption bandwidth and corrosion resistance have a great value in aircraft and vessel fields.