Abstract: Rare earth elements serve as critical strategic resources, playing an irreplaceable role in high−tech industries such as new energy materials, aerospace, and military manufacturing. As global demand for strategic resources continues to rise and research on deep−sea mineral resources advances, the extraction and utilization of deep−sea rare earth deposits have emerged as a key focus in international mineral resource studies. Deep−sea rare earth elements are predominantly hosted in sediments characterized by high clay mineral content, poor mineral liberation, and fine grain size. As a novel type of rare earth resource, deep−sea sediments hold reserves far exceeding those on land and are notably enriched in medium and heavy rare earth elements, offering significant strategic value for securing future supplies to high−tech industries. These elements often occur in adsorbed or isomorphous forms within fine mineral particles, such as biogenic apatite, resulting in low grades, fine particle sizes, and difficult liberation−posing considerable challenges for the development of efficient extraction technologies. Current methods for separating and extracting rare earth elements from deep−sea sediments include hydrometallurgical processes, combined physical separation and beneficiation techniques, emerging green and low−carbon technologies, and in−situ collection with preliminary enrichment systems. Although acid leaching features a relatively simple process, it is associated with high acid consumption, suboptimal recovery rates, and significant environmental risks. In contrast, integrated approaches−such as those combining particle size separation with flotation in a staged flotation−smelting process, or systems that incorporate in−situ pre−enrichment, pipeline transport, and modular refining−show greater promise for improving recovery efficiency while reducing transportation and environmental impacts. Numerous evaluation studies on seabed mining and beneficiation technologies have been reported, offering insights into future directions for rare earth separation and extraction methods by considering economic feasibility, environmental sustainability, and resource potential. Future technological development must be closely aligned with the specific occurrence states of rare earth elements, optimize integrated beneficiation−metallurgy flowsheets, and address the challenges of technical viability and economic feasibility under extreme deep−sea conditions.