Abstract: objective To explore the difference of intestinal flora composition between IgA nephropathy ( IgAN) patients and healthy control by 16S rDNA sequencing technology. Methods Ten patients with primary IgAN and 10 healthy people with balanced age, gender, and renal function were selected for a case-control study. Species annotation and abundance analysis were carried out using 16S rDNA technology based on Illumina NovaSeq sequencing platform, and the flora composition and structure of the two groups of samples were compared. Results The composition of intestinal flora was significantly different between the IgAN group and the healthy control. At the level of phylum classification, the relative abundance of firmicutes increased significantly in the IgAN group compared with the healthy control, while the relative abundance of bacteroidetes and actinomycetes decreased significantly compared with the healthy control. On the level of classification, the number of megomonas in the IgAN group increased significantly compared with the healthy control, while the number of bifidobacterium decreased significantly compared with the healthy control. Conclusion The intestinal flora in patients with primary IgAN had significant changes when comparing with healthy people, which might be the underlying pathogenesis of IgA nephropathy.