Objective: To explore the relationship between gut microbiota and chronic radiation enteritis of cervical cancer patients. Methods: Fecal samples were collected from 34 patients with cervical cancer who had received radiotherapy for at least 6 months but less than 2 years. The patients were divi-ded into mild toxicity group (mild, M) with no symptoms or mild symptoms and severe toxicity group (severe, S) with severe symptoms by clinical diagnosis of radiation enteritis, modified inflammatory bo-wel disease questionnaire (IBDQ) and Vaizey questionnaire. DNA extracted from fecal samples was sequenced and analyzed by 16S rRNA sequencing method. The analysis indexes included α-diversity, β-diversity, taxonomic composition analysis, taxonomic hierarchy tree and linear discriminant analysis (LDA) effect size (LEfSe). Results: From the perspective of species diversity, most indices of α diversity in group M were higher than those in group S. Although there was no significant difference, it also indicated a correlation between low species diversity and severity of intestinal symptoms to some extent. There was also a significant difference in the distribution of β diversity between the two groups, indicating that the microbial characteristics were different between the two groups. From the perspective of species composition, the M group had higher Firmicutes [66.5% (M) vs. 56.0% (S)] and lower Proteobacteria [4.1% (M) vs. 13.9% (S)] than the S group at the level of phyla. At the level of genus, there were also significant differences between the two groups: Shigella [2.7% (M) vs. 8.5% (S)], Faeca-libacterium [7.0% (M) vs. 2.7% (S)], Lachnospiraceae_Clostridium [1.3% (M) vs. 4.7% (S)]. Through LEfSe also found some species with statistically significant differences between the two groups. The abundance of Peptoniphilus, Azospirillum and Actinomyces in group M was significantly higher, while the abundance of Veillonellaceae, Rhodobacteraceae, and Rhodobacterales in group S was significantly higher. The taxonomic hierarchy tree also intuitively showed the difference in species composition between the two groups at each taxonomic level in space. Conclusion: The severity of chronic radiation enteritis of cervical cancer is closely related to the characteristics and composition of gut microbiota.