Abstract: With the rapid development of 5G communication technology, wireless devices with diverse functions are widely used in both military and civilian fields, bringing convenience but also generating significant electromagnetic radiation and causing electromagnetic pollution issues. Novel microwave absorbing materials that are lightweight, wide-band, and high in absorption rate are currently one of the hotspots in the development of absorbing materials. To achieve efficient absorption of electromagnetic waves, biomass carbon-based absorbing materials with heteroatom doping as the main modification method have increasingly become a research focus. However, a large number of studies have focused on limited or specific doping targets, without providing a comprehensive overview of the system of heteroatom-doped biomass-derived carbon-based absorbing materials. Therefore, this paper reviews the research progress of different heteroatom-doped biomass-derived carbon-based absorbing materials in recent years from both endogenous and exogenous doping methods, compares the advantages and limitations of the two, briefly discusses the influence of synthesis methods on doping uniformity, and summarizes the structure-activity relationship of heteroatom types regulating the absorbing mechanism from the perspectives of heteroatom electronegativity, atomic radius, and bonding characteristics, revealing their impact on absorbing performance. Finally, the development prospects of heteroatom-doped biomass-derived carbon-based absorbing materials are prospected. This review provides important reference value for further promoting the research on biomass-derived carbon-based absorbing materials.