Abstract: [Objective] To study the proportion and distribution of intestinal flora in patients with ulcerative colitis and Crohn's disease, and to analyze its correlation with ulcerative colitis and Crohn's disease.[Methods] 118 patients with inflammatory bowel disease(IBD) admitted to our hospital from January 2016 to January 2019 were selected as the study subjects, including 72 patients with ulcerative colitis and 46 patients with Crohn's disease.Another 60 healthy volunteers were selected as control group during the same period.Data of erythrocyte sedimentation rate(ESR), C-reactive protein(CRP), white blood cell count(WBC) and platelet count(PLT) were collected, the numbers and positive detection rates of Bacteroides intestinalis(BD), Bifidobacterium(BL), Eubacterium spp.(ES), Clostridium minimus(CD), Lactobacillus(LC), Peptococcus(PS), Enterobacter(EMB), saccharomycetes(SB), Staphylococcus(SP), and Enterococcus(EC) were detected, Logistic regression analysis was used to analyze the related factors of ulcerative colitis and Crohn's disease.[Results] The levels of ESR, CRP, WBC, and PLT in ulcerative colitis group and Crohn group were significantly higher than those in control group(P<0.05).The number of intestinal pathogenic bacteria BD, SB, EC, EMB, probiotic BL, LC, PS, CD of neutral bacteria in ulcerative colitis group were significantly higher than those in control group(P<0.05), and the level of ES of neutral bacteria was significantly lower than that in control group(P<0.05);the number of intestinal pathogenic bacteria BD, SB, EC, EMB, probiotic BL, LC and PS in Crohn group were significantly higher than those in control group(P<0.05), the CD and ES levels of neutral bacteria were significantly lower than those of the control group(P<0.05).The positive detection rates of intestinal pathogenic bacteria BD, EC, probiotic BL and LC in ulcerative colitis group were significantly higher than those in control group(P<0.05), the positive detection rates of pathogenic bacteria EC and probiotics LC in the three groups were significantly different(P<0.05).The correlation analysis showed that the number of SB in ulcerative colitis group was positively correlated with ESR(P<0.05), the numbers of BL, EMB, and EC were positively correlated with CRP(P<0.05), the number of ES was negatively correlated with WBC(P<0.05), the number of EC was positively correlated with WBC(P<0.05), and the numbers of EMB and EC were positively correlated with PLT(P<0.05).The numbers of EMB and EC in Crohn group were positively correlated with CRP level(P<0.05).The high numbers of pathogenic bacteria(SB, EC, EMB) and low numbers of probiotics(BL, LC) in intestinal tract were the risk factors for ulcerative colitis and Crohn's disease(P<0.05).[Conclusion] The intestinal flora of patients with ulcerative colitis and Crohn's disease is unbalanced, the number of pathogenic bacteria increases, high number of pathogenic bacteria and low number of probiotics are risk factors for ulcerative colitis and Crohn's disease.