To address the issue of electromagnetic pollution exacerbated by new wireless communication technologies, the development of efficient electromagnetic wave (EMW) absorption materials is crucial. MXenes, as a typical class of two-dimensional nanomaterials, have gained attention as efficient EMW absorbers due to their abundant surface chemistry, large specific surface area, excellent electrical conductivity, and good mechanical properties. However, the preparation of novel MXenes and the elucidation of their electromagnetic wave absorption mechanisms remain to be further explored. This paper first provides a review of the preparation processes of MXene materials, with a focus on traditional MXene preparation methods such as HF etching, HF in-situ etching, and molten salt etching, and also discusses the prospects for the preparation of high-quality MXenes and new multi-component MXenes. In terms of EMW absorption, the paper emphasizes the impact of MXene morphology design, defect engineering (such as doping and vacancies), and the construction of heterogeneous structures (composites with magnetic, dielectric, and polymeric materials) on the EMW absorption performance. Based on these factors, design strategies for MXene-based EMW absorption materials are proposed. Additionally, the electromagnetic wave absorption mechanisms of MXene-based materials are clarified, and future prospects for multifunctional and ultra-broadband EMW absorption applications of MXene-based materials are discussed.