• Dual-loss MXene/NZFO heterogeneous nanocomposites were successfully synthesized via a simple in-situ hydrothermal method. • The excellent EMA ability originated from magnetic-dielectric synergy effect, more polarization loss and transmission paths. • The optimized MXene/NZFO nanocomposites exhibit the maximum RL value of − 66.2 dB at 15.2 GHz with a thickness of 1.609 mm. • The EMA performance of MXene/NZFO heterogeneous nanocomposites can be controlled through regulating ratio of MXene. [Display omitted] With the boosting development of wireless communication, highly efficient electromagnetic wave absorption (EMA) materials are urgently need in military and civilian fields. However, how to combine magnetic loss and dielectric loss materials effectively to achieve highly efficient EMA efficiency remains a challenge. Herein, dual-loss Ti 3 C 2 T x MXene/Ni 0.6 Zn 0.4 Fe 2 O 4 (MXene/NZFO) heterogeneous nanocomposites were successfully synthesized by incorporation of magnetic NZFO nanoparticles onto the surface and between the layers of MXene via a straightforward in-situ hydrothermal method. The MXene/NZFO heterogeneous nanocomposites hold outstanding electromagnetic wave attenuation ability, which can be attribute to the impedance matching, magnetic-dielectric synergy effect, more interfaces polarization and increased transmission paths. In particular, the optimized MXene/NZFO-2 heterogeneous nanocomposites exhibit an excellent microwave absorption performance that the maximum reflection loss (RL) reaches up to −66.2 dB at 15.2 GHz and an effective absorbing bandwidth of 4.74 GHz with the thickness of only 1.609 mm. Therefore, this work provides a new insight to design and construct excellent EMA candidates with multiple loss, which be favorable to solve electromagnetic pollution problems. [ABSTRACT FROM AUTHOR]