With the rapid development of electronic information technology and the 5G, wireless electronic communication technologies and related products based on electromagnetic wave emission, transmission, and processing become popular. However, the consequent electromagnetic radiation and interference are serious, affecting human-being health and environment. Also, , the survival and penetration capabilities of weapon systems require minimizing radar cross-sections to achieve electromagnetic stealth with the continuous advancement of modern warfare radar detection technologies. The adoption of electromagnetic wave-absorbing materials currently represents the most effective and feasible approach to mitigate electromagnetic pollution and realize electromagnetic invisibility goals. For the dual needs of civil and defense applications, the development and production of high-performance electromagnetic wave absorbents becomes a hot research topic. Moreover, high-performance absorbing materials meet the basic requirements for traditional absorbents of "light weight, strong absorption, thin thickness, and wide band", and possess properties like high-temperature resistance, corrosion resistance, etc., to adapt to different complex environments.SiC fibers have attracted extensive attention due to their superior properties of low density, high strength, high modulus, high-temperature resistance, oxidation resistance, and corrosion resistance. SiC fibers have a tremendous application value in various extreme environments, including nuclear reactors, aeroengines, aircraft nozzles, etc.. Moreover, as a wide bandgap semiconductor material, SiC fibers also possess the advantage of tunable electrical resistivity, providing possibilities for their functional application in electromagnetic wave absorption. However, the electromagnetic absorption performance of conventional SiC fibers is far from ideal due to the presence of some issues such as single loss mechanism and impedance mismatch. It is thus necessary to improve the electromagnetic wave absorption capabilities of SiC fibers. To enhance the absorption performance of SiC fibers, efforts could be made in the following two aspects, i.e., tuning the electrical resistivity of SiC fibers to augment dielectric loss and optimize impedance matching, and introducing new loss mechanisms to increase electromagnetic wave attenuation paths. This review represented four approaches and underlying mechanisms to improve the electromagnetic wave absorption performance of SiC fibers, namely, elemental doping, surface coating design, structural design, and microstructure manipulation through thermal treatment. Furthermore, from the perspective of fibers, interface, matrix, and their structures, the related research progress on the electromagnetic wave absorption capabilities of SiC fiber-reinforced ceramic matrix and polymer matrix composites was summarized. The electromagnetic wave absorption properties could be effectively enhanced via the rational design of the SiC fibers and composites in multiple length scales.Summary and prospects The mechanisms underlying the four approaches to improve the electromagnetic wave absorption performance of SiC fibers are not entirely the same. Element doping can form conductive phases, magnetic loss phases, and heterogeneous interfaces inside SiC fibers to increase their electromagnetic losses, thus improving the electromagnetic wave absorption performance. Surface coating design can increase electromagnetic wave loss mechanisms, while optimizing impedance matching to attenuate electromagnetic waves. Structural design enables more electromagnetic waves to enter the interior of SiC fibers and utilizes structural features to increase electromagnetic wave transmission distance and multiple reflections, effectively attenuating electromagnetic waves and improving absorption performance. Thermal treatment can regulate the composition and crystallite size (microstructure) of SiC fibers, causing changes in fiber electrical resistivity and electromagnetic parameters, thereby improving electromagnetic wave absorption. For SiC fiber-reinforced composites, the multidimensional design of SiC fibers, interface, matrix, and their structures can enhance absorption performance. However, despite many achievements in the research of electromagnetic wave absorption properties of SiC fibers and their composites, studies on the synergistic improvement of structure absorption and other functional properties of SiC fiber-reinforced composites are still scarce. It is thus necessary for the functional application of SiC fibers in complex environments to strengthen the synergistic design of SiC fiber structural units in different scales and the research on structure-property evolution of SiC fiber reinforced electromagnetic wave absorbing composites under service conditions.