Abstract: Pollutants from land and coastal aquaculture lead to the serious eutrophication of China's coastal and estuary waters. In this study, Salicornia europaea, which can grow in tidal zone, and with highly salty and alkaline-tolerant characteristics, was used to investigate its purification effect on eutrophic seawater through cultivating on floating bed. A circulating water system with flounder culture pond and floating bed purification pond was constructed to simulate the continuously polluted eutrophic seawater environment. By transplanting the seedlings of Salicornia europaea on the floating bed, the changes of 4 nutrient indexes, including ammonia nitrogen (NH₄⁺-N), nitrate nitrogen (NO₃^--N), nitrite nitrogen (NO₂^--N) and phosphate (PO₄^3--P) concentrations in different water bodies, as well as the survival and growth of plants, were measured to study the purification effect of Salicornia europaea. The results show that the notable absorption of NH₄⁺-N and NO₂^--N by Salicornia europaea was observed (P < 0.05), and the maximum removal rate was 32.97% for NH₄⁺-N and 35.66% for NO₂^--N under the hydraulic retention time of 12 h, respectively. However, for PO₄^3--P and NO₃^--N, there was some but not significant removal effect. The survival rate of Salicornia europaea on the floating bed was more than 93%, and the plants had obvious growth. Within 25 days, the overall length of plant increased by about 12%, the fresh weight increased by 102%, and the dry weight increased by 83%. The findings of this study suggest that Salicornia europaea can be used as a tool plant for the ecological floating bed to purify the eutrophic seawater near the shore and at the estuary, and provide technical support for the protection of the marine ecological environment.