Objective To compare the differences in the composition and diversity of intestinal flora between knee osteoarthritis(KOA)patients with dampness-heat obstruction syndrome,cold-dampness blockage syndrome and healthy people;To explore the characteristics of intestinal flora of KOA patients with the above two TCM syndrome types.Methods According to the inclusion and exclusion criteria,dampness-heat obstruction syndrome group,cold-dampness blockage syndrome group,and healthy control group were screened,with 10 cases for each group,and then their fecal samples were collected.16S rDNA sequencing technology was used to compare the differences of intestinal flora among groups by Alpha and Beta diversity analysis.Results There was no significant difference in species richness of intestinal flora among the three groups,but there was statistical significance in species diversity between cold-dampness blockage syndrome group and dampness-heat obstruction syndrome group,and healthy control group(P<0.05).There were statistical significance among the three groups in intestinal flora composition(P= 0.001).At the phylum level,Bacteroidota and Firmicutes were significantly dominant,and at genus level,the abundance of Prevotella in dampness-heat obstruction syndrome group and cold-dampness blockage syndrome group increased.The abundance of Enterobacteriaceae,Lachnospira and Klebsiella was relatively large in dampness-heat obstruction syndrome group.The abundance of Prevotella and Pseudomonas in cold-dampness blockage syndrome group was large.Conclusion There are differences in the intestinal flora structure between KOA patients with dampness-heat obstruction syndrome and cold-dampness blockage syndrome.