Interconnected carbon nanosheets anchored with Fe3O4 nanoparticles (Fe3O4@CNS) composite was prepared via a scalable method involving spray drying and high-temperature calcination processes. Fe3O4 nanoparticles with an average diameter about 13 nm were uniformly distributed on the carbon nanosheets. A broad absorption bandwidth (RL < -10 dB) of 7.99 GHz (9.67-17.66 GHz, corresponding the wavelength range of 3.10-1.70 cm) was achieved with the thickness of 2.8 mm, and the minimum reflection loss of - 41.2 dB was obtained with the thickness of 3.0 mm. It is believed that the Fe3O4@CNS nanocomposite with high-performance electromagnetic wave absorption can be a promising candidate for practical application.