In order to prepare electromagnetic wave attenuation materials in wide-band, the hydrothermal method was used to prepare graphene/copper nickel ferrite composite (CNFRGO), and the composite was characterized by SEM, XRD, IR and Raman spectrum. Secondly, the electromagnetic parameters of the composite were measured at 2-18 GHz. Moreover, the loss tangent and reflection loss were calculated to analyze its microwave attenuation performance. Finally, its complex refractive index in IR band was measured, and its extinction and absorption properties were calculated and analysed by using the measured data and the T matrix method. The results show that the spinel-type copper nickel ferrite nanoparticles are adsorbed on the surface of reduced graphene oxide, and the particle size is mostly around 20 nm. CNFRGO have both dielectric and magnetic loss, and the bandwidth of its reflection loss lower than -10 dB is 3.7 GHz, and its peak is -14.7 dB at 11.8 GHz. In near-IR band, the strong extinction of CNFRGO is mainly caused by scattering. It′s mainly due to absorption in middle and far IR band, and its absorption ability in near and middle IR band is strong, but it′s relatively weak in far IR atmospheric window. Therefore, microwave and IR radiation can be absorbed simultaneously by CNFRGO, and it′s a good microwave and infrared compatible material.