Abstract: Polysaccharides from marine organisms are an important source for researching and developing innovative carbohydrate-based drugs. Echinoderms, such as sea cucumber, starfish, sea urchin, and brittle star, are rich in resources. The polysaccharides from these species exhibit unique structural features and possess extensive, potent pharmacological activities, making them promising lead compounds for carbohydrate drug development. In recent years, significant progress has been made in the isolation and purification, structural analysis, and activity evaluation of marine echinoderm polysaccharides. Notably, the fine structures of several polysaccharides have been elucidated, and several novel polysaccharides with nanomolar-level activity have been identified. However, numerous challenges and deficiencies remain in the research areas related to structural elucidation, structure-activity relationships, and mechanisms of action. This review systematically summarizes the progress and breakthroughs in the study of marine echinoderm polysaccharides and provides new insights and suggestions, which may offer important reference information for the research and development of low-toxicity, high-efficiency marine carbohydrate drugs, thereby advancing the field of marine-derived pharmaceuticals.