Abstract: Ascites syndromes disease is a common and ubiquitous disease in the industrial culture with turbot, which often results in turbot's massive mortalities. In June 2006, an outbreak of ascites syndromes disease of the cultured turbot Scophthalmus maximus occurred in an indoor farm in Shandong Province of China. Through the isolation, purification as well as cultivation of the bacteria in the diseased fish, and by tracing the bacteria in the well water, rearing pond water along with the feeding trash fish, it was found that the bacterium RF-1 which existed in the trash fish was similar to the bacterium FS-1 in the diseased turbot; artificial infection test demonstrated that the bacteria RF-1 and FS-1 had the same infection symptoms for healthy turbots. Further researches such as traditional physiological and biochemical test, API-ID32E test as well as 16S rRNA sequence analysis were also carried out. The results showed that the bacteria RF-1 and FS-1 were both Virio alginolyticus. Finally, a drug sensitivity test on these two bacteria was conducted to provide medical instruction for prevention and cure of ascites syndromes disease.