Abstract: Objective: To identify the key differentially expressed genes of Chronic Spontaneous Urticaria (CSU) ，in order to provide the basis of studying the pathogenesis and targeted therapy of CSU. Methods: GSE72541 data set was downloaded from Gene Expression Omnibus (GEO) database. The differentially expressed genes between CSU group and healthy control group were screened by R language limma package. The function of differentially expressed genes, their pathway enrichment and their protein interactions were analyzed by clusterprofiler R package and STRING online software and the MCODE plug-in of Cytoscape 3.8.2 Software. Results: The 86 differentially expressed genes in CSU group and healthy control group were screened, which including 64 up-regulated genes and 22 down-regulated genes (|logFC|>1 & adj.P.Val<0.05). GO enrichment analysis showed that the differentially expressed genes were mainly concentrated in biological processes such as platelet activation, blood coagulation and neutrophil degranulation; KEGG analysis showed that it was mainly related to hematopoietic cell line, graft-versus-host disease, Staphylococcus aureus, etc. In addition, the established PPI network screened 62 nodes and 14 key genes (CXCL10, MMP9, SELP, MME, ITGB3, CLU, GP6, C5AR1, C6orf2, GP1BB, VWF, CR1, GP9, PLAU). Conclusion: ITGB3，ITGA2B，MMP9, CR1 and other genes may be closely associated with the pathogenesis of CSU.

Key words: urticaria, pathogenesis, bioinformatics, differentially expressed genes