The efficacy of Xiangmei Pills on rats with ulcerative colitis(UC) was investigated by characterizing the spectrum of the active chemical components of Xiangmei Pills. Rapid identification and classification of the main chemical components were performed,and the therapeutic effects of Xiangmei Pills on the proteins and intestinal flora of UC rats were analyzed to explore the mechanism of its action in treating UC. Fifty SD rats were acclimatized to feeding for 3 d and randomly divided into blank group, model group,mesalazine group(0. 4 g·kg~(-1)), low-dose group of Xiangmei Pills(1. 89 g·kg~(-1)), and high-dose group of Xiangmei Pills(5. 67 g·kg~(-1)), with 10 rats in each group. 5% dextrose sodium sulfate(DSS) was given by gavage to induce the male SD rat model with UC,and the corresponding medicinal solution was given by gavage after 10 days, respectively. The therapeutic effect of Xiangmei Pills on rats with UC was evaluated according to body mass, disease activity index(DAI), and hematoxylin-eosin(HE) staining, and the histopathological changes in the colon were observed. Ultra-high performance liquid chromatography-quadrupole/electrostatic field orbitrap high-resolution mass spectrometry(UHPLC-Q-Orbitrap HRMS) technique was used to rapidly and accurately identify the main chemical constituents of Xiangmei Pills. Immunohistochemistry was used to detect the expression of aryl hydrocarbon receptor(AhR),interferon-γ(IFN-γ), mucin-2(MUC-2), and cytochrome P450 1A1(CYP1A1) in colon tissue. Interleukin-22(IL-22) expression in colon tissue was detected by immunofluorescence. The 16S r DNA high-throughput sequencing technique was used to study the modulatory effects of Xiangmei Pills on the intestinal flora structure of rats with UC. Pharmacodynamic results showed that compared with that of the blank group, the colon tissue of the model group was congested, and ulcers were visible in the mucosa; compared with that in the model group, the histopathology of the colon of the rats with UC in the groups of Xiangmei Pills were improved, with scattered ulcers and reduced inflammatory cell infiltration. Chemical analysis showed that a total of 45 components were identified by mass spectrometry information, including 15 phenolic acids, 8 coumarins, 15 organic acids, 3 amino acids, 2 flavonoids, and 2 other components. Compared with those in the blank group, the levels of Ah R, CYP1A1, MUC-2, and IL-22 proteins in the colon tissue of rats in the model group were significantly decreased, and the level of IFN-γ protein was significantly increased; the intestinal flora of rats in the model group was disorganized, with a decrease in the abundance of the flora; the relative abundance of Bacteroidetes,unclassified genera of Ascomycetes, Prevotella of the Prevotella family, and Prevotella decreased significantly, and that of Firmicutes decreased, but the difference was not statistically significant. The relative abundance of Bacteroidetes, Bifidobacterium, and Lactobacillus increased significantly. Compared with those of the model group, the levels of Ah R, CYP1A1, MUC-2, and IL-22proteins in the colonic tissue of the groups of Xiangmei Pills were significantly higher, and the levels of IFN-γ proteins were significantly lower. The recovery of the intestinal flora was accelerated, and the diversity of the intestinal flora was significantly increased. The relative abundance of Bacteroidetes was significantly increased, and that of unclassified genera of Ascomycetes,Lactobacillus, Prevotella of the Prevotella family, and Prevotella was significantly increased. The relative abundance of Bacteroidetes and Bifidobacterium was significantly decreased. This study demonstrated that Xiangmei Pills can effectively treat UC, mainly through the phenolic acid and organic acid components to stimulate the intestinal barrier, regulate protein expression and the relative abundance and diversity of intestinal flora, and play a role in the treatment of UC.