) is one of China’s major economic sea fish because of its high commercial value. In recent years, as the scale of aquaculture has expanded and the environment has deteriorated, large yellow croaker diseases have occurred frequently. Healthy culture of large yellow croaker is closely linked to the bacteria in aquaculture environments because bacteria degrade organic pollutants and play important roles in material transformation and energy flow in mariculture systems. Therefore, it is important to monitor bacterial composition in aquaculture environments to ensure sustainable development of healthy large yellow croaker. In this study, 16S rDNA was used as a molecular marker to explore bacterial community structure in large yellow croaker cage culture water by clone library construction, Restriction Fragment Length Polym­orphism (RFLP) analysis, and sequence analysis. Samples were collected from Sandu Bay Fufa aquaculture base in Ningde, Fujian province. Water samples from 5 cultivation cages were mixed and 3 liters of this mixed water were filtered to enrich the bacteria. Total DNA was extracted and used for PCR amplification of 16S rRNA genes using the bacterial universal primers 27F and 1 492R, and then the 16S rDNA clone library was constructed. From the clone library of the water sample, 154 clones were picked randomly. A total of 137 positive clones and 92 RFLP patterns were obtained from the clone library. Representative clones were sequenced, and the results revealed a high bacterial genetic diversity. Idiomarina was the second dominant group. In addition, , were also present. The results provide a foundation for investigating the relationship between healthy aquaculture of