Abstract: In order to study the optimum culture density, water quality trends and the effect on prevention diseases for Larimichthys crocea fingerling culture in recirculating aquaculture systems, an experiment on Larimichthys crocea fingerling cultivation in recirculating aquaculture systems was carried out in the period of 180d, where the fingerling size was 1.82 g/ind at three different densities (350 ind/m3,400 ind/m3 and 450 ind/m3), and there were 3 barrels for each density for parallel compare. The results showed that: 400 ind/m³ was the optimum culture density, at which, the average survival rate was 83.6%, average capture individual weight was 95.4g, and the individual weight increased per day was 0.52g. Average survival rate, capture individual weight and individual weight increased per day at the density of 400 ind/m³ were significantly higher than those at 450 ind/m3 density by 11.2%（75.2%）、27.5%（74.8g) and 28.1% (0.41g) respectively (P<0.05). FCR at the density of 400 ind/m³ was 1.28, which is significantly lower than those at 450 ind/m3 density by 22.9% (1.66) (P<0.05). But there was no significant difference between 400 ind/m³ and 350 ind/m3 density groups (P>0.05). During the trial, concentrations of total ammonia nitrogen (TAN) and NO2-N in the water were as low as 0.126 mg/L and 0.047 mg/L respectively in 400 ind/m³ density group. Both concentrations of TAN and NO2-N in 400 ind/m³group were significantly lower than those in 450 ind/m³ group by 25.3% (0.154mg/L) and 41.0% (0.063mg/L) respectively (P<0.05). But there was no significant difference between 400 ind/m³ and 350 ind/m3 density group (P>0.05). No parasitic diseases and bacterial diseases occurred during the trial. The research showed the technology of Larimichthys crocea fingerling cultivation in recirculating aquaculture systems has broad application prospects because it can effectively save water, reduce effluents, increase survival rate and promote growth.