Abstract: We evaluated the effects of dietary Clostridium butyricum supplementation on the growth performance and intestinal microbiota of juvenile Trachinotus ovatus, so as to provide a theoretical basis for the application of C. butyricum in T. ovatus aquaculture. In this study, five kinds of experimental feeds 0, 1% (1×10⁷ CFU·g⁻¹), 2% (2×10⁷ CFU·g⁻¹), 3% (3×10⁷ CFU·g⁻¹) and 4% (4×10⁷ CFU·g⁻¹) of C. butyricum had been sprayed on the basic feed to feed T. ovatus for eight weeks. The results show that dietary supplementation of 2% C. butyricum improved the feed utilization rate of juvenile T. ovatus significantly. The diversity of intestinal flora was significantly different from that in control group and 4% supplemental group (P<0.05). The principal co-ordinates analysis and principal component analysis show that the added amount of C. butyricum in the feed was the main factor for the change in the structure of the intestinal flora of juvenile T. ovatus. At phylum and genus level, C. butyricum supplemental group and control group show difference at different degrees. Dietary supplementation with C. butyricum improved the growth performance and intestinal health of juvenile T. ovatus.