Abstract: In order to explore the effects of different microbial preparations on the growth, body index and intestinal tissue structure of Micropterus salmoides, different concentrations of Clostridium butyricum 0 (group A, CK), 0.25% (group B), 0.5% (group C), 1% (group D) Clostridium butyricum (5×10⁸ cfu·g^-1), 0.2% yeast products (group E) and their mixture (0.25% Clostridium butyricum+0.2% yeast products, group F) were added to the commercial compound feed for a two-stage breeding experiment for 17 weeks. The results showed that: in the first stage (14 weeks), except for adding 0.2% yeast products (group E), the growth performance of Micropterus salmoides was significantly improved compared with the control group, and the effect of adding 0.5% Clostridium butyricum was the best. In the second stage (17 weeks), the final mean weight and final body length of 0.5% Clostridium butyricum (group C) and 0.25% Clostridium butyricum+0.2% yeast products (group F) were significantly higher than those of the control group A. There were no significant differences in the fullness, visceral-body ratio index, length of intestinal villus and muscle layer thickness among the three groups. However, compared with the control group (group A), the indexes of adding 0.5% Clostridium butyricum (group C) had an increasing tendency, and the indexes of adding 0.25% Clostridium butyricum+0.2% yeast products (group F) had a decreasing tendency. The results showed that under the experimental conditions, the addition of 0.5% Clostridium butyricum to the commercial compound feed had the best effect on the growth and improvement of intestinal health of Micropterus salmoides.