Abstract: 【Objective】This study aimed to investigate the diversity and community of microflora from the three intestinal segments(foregut, midgut, and hindgut) of koi carp(Cyprinus carpio var.koi) and provide reference for further research on the function of koi carpintestinal flora and the differentiation of physiological functions in different parts of the intestine.【Method】Microflora from the three intestinal segments, foregut, midgut, and hindgut, were collected, and the physiological and biochemical indexes of intestinal bacteria through the bacterial microbiochemical identification tube were identified based on the traditional bacterial culture technique.Genomic DNA of intestinal microflora from the three intestinal segments was extracted, and 16S rDNA high-throughput sequencing technology was used to analyze the microflora composition and diversity.【Result】The three microflora samples from the three intestinal segments(foregut, midgut, and hindgut) were sequenced to obtain 48659, 47013, 47819 effective tags, respectively.After dividing the OTUs based on 97% sequence similarity level, 1555, 1294, and 1423 OUTs were obtained, respectively.Alpha diversity analysis showed that the Shannon and Chao1 indexes of the hindgut flora samples were the highest.At the phylum level, the top five phyla with the highest abundance in the foregut, midgut, and hindgut were all Proteobacteria, Fusobacteria, Bacteroidetes, Firmicutes and Lentisphaerae, which could be probably recognized as the core bacterial taxa in the koi carpintestine, but the relative abundance of each phylum was different in different parts.The species abundance heat map constructed showed that the top ten species with the highest relative abundance were the same, but the relative abundance of some species in different parts of the intestine was quite different, such as Delft and Toxoplasma.The UniFrac cluster heat map analysis showed that the intestinal flora of the midgut and hindgut were clustered into one group, indicating that the composition of the flora of these two parts was highly similar in structure.【Conclusion】Unique microflora structures are formed in different parts of the koi carp intestinal tract, and may affect the functional differentiation of different parts of the intestinal tract.