In this article, a three-dimensional chemically reduced graphene oxide/polypyrrole nanotubes (PPy nanotubes)/FeO aerogel (GPFA) was fabricated by a simple one-step self-assembly process through hydrothermal reduction. The addition of both PPy nanotubes and FeO nanoparticles is aimed to avoid the aggregation of graphene sheets, effectively adjust the permittivity, and make better impedance matching between dielectric loss and magnetic loss of the composite aerogel to gain excellent electromagnetic (EM) wave absorption performance. The EM wave-absorbing results indicate that the ternary composite with an ultralow density of about 38.3 mg/cm shows an improved EM wave-absorbing property with a maximum reflection loss of -49.2 dB at the frequency of 11.8 GHz, with an effective absorption bandwidth below -10 dB reaching 6.1 GHz (9.8-15.9 GHz) at a thickness of 3.0 mm. Such an outstanding EM wave absorption behavior can be attributed to the multiple reflections, polarizations, and relaxation processes in the aerogel.