) is a cold-water marine fish. In recent years, with the expansion and improvementof turbot farming, bacterial disease has severely affected turbot development, especially in larvae. Becausethe fish have the special requirements for the living environment, disease occurrence is the result of interactions amongfish, pathogens, and the environment. The gastrointestinal flora plays an important role in fish growth and development,and is closely related to disease occurrence. Therefore, it is necessary to investigate the gastrointestinal flora of larvalfish. In this study, factors that influence gastrointestinal microflora formation and succession in turbot larvae were investigatedby high-throughput sequencing. The intestinal tract microflara and their relationships with different developmentstages (e.g., larvae and fertilized eggs), chlorella, rotifer, artemia, pellet feed, and tank inlet water were analyzed.The results revealed that the intestinal tract microflora of turbot larvae was stable after initial feeding and wasdirectly affected by bacteria in fertilized eggs. Meanwhile, microflora structure was stable during turbot larval developmentand barely influenced by the bacteria in water and feed. The dominant bacterium was at arelative proportion of up to 45%65% in larval intestines. In addition, the relative abundance of this bacterium in fertilizedeggs reached 10.4%. Basing on these results, we suggest that the gastrointestinal tract of turbot larvae may be selectivefor the colonized bacteria. Some bacteria in water and feed, such as the