Abstract: 【Objective】 The aim of the experiment is to study the changes of microbial abundance and bacterial structure in the contents of different parts of the small intestine of weaned foals in the hope of providing a reference basis for balancing the intestinal flora and improving the intestinal health of weaned foals. 【Methods】 Five weaned Kazakh foals with an average weight of (147.08±4.86) kg were selected for the study and kept under the same feeding management and dietary nutritional level for 60 d. The contents of duodenum, jejunum and ileum of weaned foals were collected, and the bacterial diversity of the contents of the various intestinal segments was detected using 16S rDNA high-throughput sequencing technology. 【Results】 (1) Based on Alpha analysis, the number of species, Chao1 index and ACE index observed in the contents of ileum of weaned foals were significantly higher than that of the jejunum (P<0.05); (2) At the phylum level, the dominant bacterial phylum in the duodenum, the jejunum and the ileum was the thick-walled phylum; (3) At the family level, the dominant bacterial phyla in the duodenum and the jejunum was Lactobacillus spp. and in the ileum, it was the dominant phyla Lactobacillus spp., Streptococcaceae and Enterobacteriaceae. The relative abundance of Bartonellaceae in the ileum was 154.62% higher than that in the duodenum (P<0.05); (4) At the genus level, the relative abundance of Actinobacillus spp. in the ileum was higher than that in the duodenum, with an increase of 149.54% (P<0.05); 【Conclusion】 Under the conditions of this experiment, the structure of bacterial flora in the duodenum, jejunum, and ileum of the Kazakh equine foal differes significantly and the microorganisms of the different intestinal segments show significant differences. The functions of microorganisms with significant differences are also different. The functions of microorganisms with significant differences in the duodenum are related to enzymatic catabolism and lipid metabolism; the functions of microorganisms with significant differences in the jejunum are related to polysaccharide biosynthesis and metabolism; and the functions of microorganisms with significant differences in the ileum are related to energy metabolism.