Objective:To screen inflammatory factors of ulcerative colitis(UC).Methods:Three sets of human GeneChip datasets were included from Gene Expression Omnibus(GEO).Differentially expressed genes(DEGs)from two of datasets were analyzed with R software,and intersection and combination of top 20 DEGs of UC rat GeneChip were screened to identify core genes of UC.ROC curve was used to evaluate sensitivity and specificity of core genes in another human microarray data set.CIBERSORT was used to analyze relationship between core genes and immune cells,proteins co-expressed with core gene were identified using protein-protein interaction(PPI)network diagram and analyzed for functional enrichment.Molecular docking of core genes with anti-inflamma-tory herbal medicines for treatment of UC was performed.Correlation between core genes and inflammation and effect of anti-inflamma-tory traditional Chinese medicine on core genes were verified by in vitro experiments.Results:S100A8 was screened out as core gene of UC with high sensitivity and specificity(AUC=0.953).S100A8 was positively correlated with immune inflammatory cells such as neutrophils,activated mast cells and monocytes.PPI and enrichment analysis revealed that S100A8 was related to inflammatory path-ways such as RAS signaling pathway,PI3K-AKT signaling pathway and mTOR signaling pathway.Anti-inflammatory Chinese medi-cines triptolide,baicalin and berberine had good binding force with S100A8.In vitro experiments suggest that S100A8 played an im-portant role in inflammation,triptolide,baicalin and berberine could reduce expression of S100A8.Conclusion:S100A8 may be an inflammatory core gene of UC,and it is expected to become a new therapeutic target.