Objective:To analyze the intestinal microbiota characteristics in ulcerative colitis (UC) patients with thin white fur (TWF) and yellow greasy fur (YGF), and to explore the relationship between tongue fur and intestinal microbiota in UC patients. MethodsThirty-five UC patients with TWF, 35 UC patients with YGF and 35 healthy persons were included to form UCTWF group, UCYGF group and healthy control (HC) group respectively. Fecal specimens were collected, and 16S rDNA gene sequencing and bioinformatics methods were used to analyze and compare the diversity and abundance of intestinal microbiota in each group.  Results:①Compared with HC group, the abundance and diversity of intestinal microbiota decreased significantly (P<0.001) in UCTWF group and UCYGF group, and the number of intestinal microbiota species decreased. Compared with UCTWF group, there was no significant difference in intestinal microbiota abundance in UCYGF group (P>0.05), but the number of intestinal microbiota species decreased. ②At the phylum level: compared with HC group, the intestinal microbiota of UCTWF group and UCYGF group decreased in the content of Firmicutes (P<0.05). Compared with UCTWF group, the intestinal microbiota of UCYGF group increased in the content of Cyanobacteria (P<0.05). ③At the genus level: Compared with HC group, the contents of Escherichia-Shigella and Streptococcus increased (P<0.05), while the contents of Subdoligranulum, Dorea, Ruminococcus and Roseburia decreased (P<0.05) in the intestinal microbiota of UCTWF group; Compared with HC group, the contents of Escherichia-Shigella and Lactobacillus increased (P<0.05), while the contents of Dorea, Subdoligranulum, Ruminococcus, Phascolarctobacterium and Roseburia decreased (P<0.05) in the intestinal microbiota of UCYGF group. Compared with UCTWF group, the content of Streptococcus increased (P<0.05) while the contents of Megasphaera, Alloprevotella, Prevotella and Neisseria decreased (P<0.05) in intestinal microbiota of UCYGF group. ④At the levels of class, order and family, the abundance of f_Prevotellaceae, o_Neisseriales and f_Neisseriaceae in the intestinal microbiota of UCTWF group was significantly higher than that of UCYGF group (LDA>2.0). The abundance of c_Bacilli, o_Lactobacillales, f_Streptococccaceae and f_Peptostreptococccaceae in UCYGF group was significantly higher than that in UCTWF group (LDA>2.0).  Conclusion:sThe abundance and diversity of intestinal microbiota in UC patients with thin white fur and yellow greasy fur were significantly lower than those in healthy patients. There are differences in intestinal microbiota composition and abundance between UC patients with thin white fur and UC patients with yellow greasy fur. Pathogenic bacteria increase while bacteria with potential protective effect decrease in the intestinal tract of UC patients with yellow greasy fur. Intestinal microbiota detection can provide valuable information for the modernization of tongue diagnosis.