Abstract: An experimental-scale closed recirculating seawater nursery system was constructed for the culture of breeding scallop and seed Argopecten irradians. To evaluate the feasibility of the water treatment process, water parameters in the nursery tank were monitored and operational effects of the water treatment facilities were evaluated during the experiment of nursery. The operation performance of the system revealed that the removal rate of SS by the water treatment facilities was 80% and the biofilter worked efficiently to maintain that the average concentrations of NH⁺₄-N, NO^-₂-N and COD were 0.023 mg/L, 0.004 mg/L and 1.43 mg/L, respectively in the nursery tank. The results demonstrated that the water treatment process was feasible and the recirculating system could be successfully used for seed Argopecten irradians nursery.