Abstract: Objective To explore the characteristics of intestinal flora in patients with chronic kidney disease(CKD) and provide rationales for preventing and treating CKD from the theory of "gutkidney axis". Methods From November 2018 to October 2019, 89 non-dialysis patients with CKD stage 2-5 were recruited. Intestinal flora was tested by 16S rRNA high-throughput sequencing. And intestinal flora alpha diversity was examined by Qiime software. The dominant bacterial phylum was defined as the highest abundance of gut bacteria and its difference was compared among different CKD stages. Results Characteristics of bacteria phylum:Top 4 bacterial phylum were Firmicutes, Actinobacteria, Bacteroidetes and Proteobacteria accounting for 98.89% of total intestinal flora. The proportion of Firmicutes as the dominant phyla in CKD3/4/5 stage was higher than that in CKD2 stage. The proportion of Actinomycetes and Proteobacteria as the dominant phyla was lower than that in CKD2 stage. And the differences were statistically significant in Firmicutes as the dominant phyla compared between CKD5 and CKD2 stages and Actinomycetes as the dominant phyla compared between CKD3 and CKD2 stages(P< 0.05). Characteristics of bacteria genus:Top 10 bacteria genus were Bifidobacterium, Bacteroides, Faecalibacterium, Streptococcus, Escherichia-Shigella, Ega-monas, Subdoligranulum, Ruminococcus, Roseburia and Agathobacter. Abundance of Bifidobacterium in CKD2 was higher than that in CKD3/4/5 stage and abundance of Faecalibacterium, Escherichia-Shigella, Subdoligranulum, Ruminococcus and Agathobacter in CKD2/3/4 stage was lower than that in CKD5 stage. And the differences were not statistically significant(P>0.05). Conclusion Firmicutes, Actinobacteria, Bacteroidetes and Proteobacteria are the dominant intestinal flora in non-dialysis CKD patients. With worsening renal function, the diversity of intestinal flora decreases in CKD patients. Some beneficial bacteria decrease and harmful bacteria increase. Clinical implications are worth exploring.