Abstract: OBJECTIVE To analyze the chemical compositions of Sophora japonica water extract, and to explore its therapeutic effects on ulcerative colitis mice and related mechanisms. METHODS HPLC-Q-Orbitrap-MS was used to qualitatively identify the chemical compositions, the data was analyzed and compared with database(mzCloud, mzVault, ChemSpider). Forty-two male BALB/c mice were randomly divided into 6 groups:normal group, model group, low, medium and high-dose groups of water extract of Sophora japonica, and positive control group, 7 in each group. The normal group was given drinking water, the other groups were administrated with 4% dextran sulphate sodium aqueous solution. All groups were given orally by gavage for 11 d at a dose of 10 mL·kg^-1. The changes of disease activity index(DAI) and microscopic pathological examination of colon tissue were observed. The levels of TNF-α and IL-1β in plasma were determined by ELISA. The expression of NF-κB p65 was detected by immunohistochemistry. RESULTS Three hundred twenty three compounds were matched in the database mzCloud, of which 22 were more than 90% matched. Compared with the model group, the colon length was longer and DAI index was lower in Sophora japonica water extract groups. The expression of NF-κB p65 in colon tissue was decreased, and the contents of TNF-α and IL-1β in plasma were decreased in a dose-dependent manner. CONCLUSION The Sophora japonica water extract can alleviate ulcerative colitis injury induced by dextran sulphate sodium in mice by inhibiting intestinal inflammatory reaction.