Carbon-based materials, characterized by their high specific surface area and exceptional chemical stability, have become integral to adsorption-based remediation methods. Carbon materials demonstrate exceptional efficiency, selectivity, and environmental compatibility in radionuclide adsorption. However, the practical application of conventional carbon materials is limited by their insufficient adsorption capacity and selectivity. Plasma modification has emerged as a highly effective strategy for enhancing the surface chemistry of carbon materials, thereby significantly improving their adsorption performance. This process increases the specific surface area of carbon materials and introduces a variety of functional groups, which in turn boost their capacity to adsorb radionuclides. This review systematically explores the progress made in modifying carbon-based adsorbents for the remediation of radioactive nuclides, with a particular emphasis on the mechanisms and effectiveness of plasma modification, covering studies on plasma-modified carbon materials for radionuclide adsorption published between 2009 and 2024. Furthermore, the review discusses the future prospects and practical applications of plasma-modified carbon materials in nuclear wastewater treatment, providing a scientific foundation for the development of efficient and sustainable remediation technologies.