Abstract: The 16S rDNA sequencing method was adopted to study the effects of mulberry leaf flavonoids, polysaccharides and alkaloids on intestinal microflora in db/db diabetic mice. The animal experiment was examined by the Ethics Committee of Nanjing University of Chinese Medicine. Ten db/m mice were control group and forty db/db mice were randomly divided into model group, metformin group, mulberry flavonoid (MF) group, mulberry polysaccharide (MP) group and mulberry alkaloid (MA) group. After intragastric administration for six weeks, fresh feces were collected for detection of intestinal microflora. There were Firmicutes, Bacteroidetes, Proteobacteria, Saccharibacteria, Tenericutes, Deferribacteres, Verrucomicrobia, Cyanobacteria in each group. The results showed that the intestinal microflora of db/db mice changed significantly from phylum level to genus level. The proportion of Firmicutes and Proteobacteria in model group decreased significantly, and the proportion of Bacteroidetes increased. The difference in species abundance distribution between model group and other groups was significant, which indicated that the community distribution was disordered in model group. After administration, the Bacteroidetes, Lachnospiraceae, Roseburia and Desulfovibrio were effectively regulated, especially in the alkaloid group. The difference in species abundance distribution between drug-treated group and blank group also became smaller. It is suggested that the active components of mulberry leaf have the effect of improving the intestinal microflora imbalance in db/db mice.