OBJECTIVE：To study the improvement effect of Shenling baizhu p owder on irritable bowel syndrome with diarrhea（IBS-D）model mice with anxiety ，and to elucidate its mechanism from the point of view of intestinal microecology. METHODS：C57 BL/6 mice were randomly divided into blank control group ，model group ，Shenling baizhu powder group （3.6 g/kg），with 8 mice in each group. Except for blank control group ，IBS-D model with anxiety was established in model group and Shenling baizhu powder group by giving corticosterone subcutaneously combined with intragastric administration of Folium Sennae decoction and chronic restraint treatment. After modeling ， blank control group and model group were given intragastric administration of normal saline ，and Shenling baizhu powder group was given relevant medicine intragastrically ，for consecutive 4 weeks. After last medication ，loose stools rate ，diarrhea index ，body weight ，sugar water preference percentage ，the times of crosssing open field center area and minimum pain threshold as well as the levels of BDNF in hippocampal tissue and 5-HT in serum were detected in each group. The cecal contents of mice in each group were extracted for microbial DNA extraction and sequencing； the abundance and diversity of intestinal microorganisms were analyzed by Alpha and Beta diversity analysis. RESULTS ： Compared with blank control group ，body weight ，sugar water preference percentage ，the times of crossing open field center area and minimum pain threshold as well as the levels of BDNF in hippocampal tissue ，relative abundance of Firmicutes phylum microorganism in intestine ， relative abundance of Lachnospiraceae_NK4A136_group genus microorganism were decreased significantly （P＜0.05）；loose stools rate，diarrhea index ，serum level of 5-HT，relative abundance of Verrucomicrobia phylum microorganism and relative abundance of Ackermann phylum microorganism were increased significantly （P＜0.05），and there were great differences in the types of intestinal microorganisms. Compared with model group ，body weight ，sugar water preference percentage ，the times of crossing open field center area ，minimum pain threshold ，BDNF level of hippocampus ，relative abundance of Firmicutes phylum microorganism，relative abundance of Lachnospiraceae_NK4A136_group genus microorganism were increased significantly （P＜ 0.05 or P＜0.01）；loose stools rate ，diarrhea index ，serum level of 5-HT，relative abundance of Verrucomicrobia phylum microorganism and relative abundance of Ackermann phylum microorganism were decreased significantly （P＜0.05），and and there were great differences in the types of intestinal microorganisms. CONCLUSION ：Shenling baizhu powder can improve the diarrhea and anxiety behavior of IBS-D model mice with anxiety ，increase the level of BDNF in hippocampus and decrease serum level of 5-HT. Its mechanism may be related to decreasing relative abundance of Verrucomicrobia phylum microorganism and Ackermann phylum microorganism ，increasing the relative abundance of Firmicutes phylum and Lachnospiraceae_NK4A136_group genus microorganism.