Objective: To screen the differentially expressed genes in peripheral blood of patients with unstable angina and acute myocardial infarction, and to explore the molecular function classification, biological network regulation and key nodes of differentially expressed genes. Methods: Gene chip data of the peripheral blood of patients with acute coronary syndrome was downloaded the from Gene Expression Omnibus (GEO) database, functional enrichment analysis was conducted by Database for annotation, visualization and integrated discovery (DAVID) website, protein-protein interaction network was constructed by Search tool for recurring instances of neighbouring genes (STRING) website. Hub genes were screened out from the network. Results: 750 differentially expressed genes were screened, of which 370 genes were up-regulated and 380 genes were down-regulated. Functional enrichment analysis showed that differentially expressed genes were mainly involved in biological processes such as extracellular matrix composition and transcriptional activity regulation. Pathway analysis showed that differentially expressed genes were mainly involved in amino acid metabolism signaling pathways and tumor-related signaling pathways. 20 hub genes were obtained by Degree algorithm analysis, IGF1, MDM2, KCNA1, OPALIN, AQP4, SMAD4, AKT2, PML, UBE3A, CDK6, VEGFA, POMC, BDKRB1, BDKRB2, AGTR2, CPR39, EDNRA, SOX9, CD274 and CTLA4. Conclusion: This study provides a basis for the mechanisms, diagnostic biomarkers, and therapeutic targets of acute coronary syndrome through bioinformatics analysis of differential genes and pathways.