Abstract With the rapid development of electronic communication technology, electromagnetic pollution has become increasingly severe, leading to a growing need for absorption materials with excellent absorption performance. Herein, nano-sized oxide-intercalated Ti 3 C 2 T x MXene composites were synthesized via γ -radiation in an aqueous system. The synthesis was conducted in a reducing environment at room temperature, which effectively prevented the oxidation of MXene. Nano-oxides (Fe 2 O 3 and Cu 2 O) were formed in situ between the MXene layers, forming a homogeneous oxide-intercalated structure. Compared with the original MXene, the intercalated structure significantly enhanced the electromagnetic wave absorption (EMA) performance of the MXene/Fe 2 O 3 composite in the frequency range of 2–18 GHz, with smaller reflection loss (RL) (−58.7 dB), thinner thickness (2.35 mm). The RL min value of the MXene/Cu 2 O composite was −50.9 dB (2.55 mm) and the effective frequency width was 4.88 GHz at a thickness of 1.3 mm. Compared with ordinary chemical methods, the γ -radiation is a facile and ‘green’ method that is suitable for large-scale preparation. The absorption mechanism was attributed to conductive loss, polarization loss, and magnetic loss, which contributed to efficient EMA. This work demonstrates that γ -radiation is a promising method for preparing nano metal oxide-intercalated MXene with enhanced EMA performance.