To explore the mechanism of intestinal remodeling during the early development of Yangtze sturgeon (Acipenser dabryanus) under artificial breeding conditions, this study applied high-throughput sequencing technology to study the structural characteristics and correlation between the intestinal microbiota and biological feed, Tubificidae, in the early developmental stage of the fish. The results showed that Proteobacteria was the dominant phylum in the intestine of A. dabryanus before feeding, and Proteobacteria and Firmicutes were the main bacteria during the 10th to 40th day of feeding. At the genus level, during the period from not feeding to the 20th day of feeding, the intestinal microbiota was relatively singular, with Pandoraea occupying an absolute dominant position, accounting for more than 88%. On the 30th day of feeding, the intestinal microbiota of A. dabryanus underwent reorganization, with species richness and diversity reaching their peak. The dominant genera became Citrobacter, Lactococcus, Plesiomonas, Staphylococcus, Aeromonas, and Klebsiella. Procrustes analysis showed that, on the 40th day of feeding, the intestinal microbiota of A. dabryanus tended to be consistent with the microbial community composition of the biological feed, Tubificidae, showing a highly significant correlation (P＜0.01). SourceTracker analysis verified that 18.97% of the A. dabryanus intestinal community on the 10th day of open feeding came from the biological feed, Tubificidae. On the 20th day of open feeding, it decreased to 0.15%, and on the 30th day of open feeding, it increased to 51.22%. On the 40th day of open feeding, it reached as high as 97.55%. This study indicated that when feeding A. dabryanus the biological feed, Tubificidae, a turning point in the early developmental stage of the intestinal microbiota occurs on the 30th day of feeding. At this time, the characteristics of the intestinal microbiota changed from high conservatism to good plasticity. Continuing feeding until the 40th day, the intestinal microbiota showed a high consistency with the biological feed microbial community. The results provided a reference for the regulation of intestinal microbiota and healthy cultivation of A. dabryanus in the early development.