Atherosclerosis (AS) is one of the main risk factors of ischemic cardiovascular and cerebrovascular diseases. Buyang Huanwu decoction (BYHWT) is a classic Chinese medicine prescription that is used for treating AS. However, the underlying pharmacological mechanism remains unclear. This study aims to clarify the molecular mechanism of BYHWT in treatment of AS through network pharmacology and in vitro experiments. Molecular structure information and targets of core components of BYHWT were obtained from PubChem and UniProtKB databases. Genes involved in AS were obtained from DisGeNet, GeneCards and OMIM databases. The core targets of BYHWT in AS treatment were identified by protein-protein interaction (PPI) network analysis with STRING platform, and analyzed by gene ontology (GO) analysis and the Kyoto Encyclopedia of Genes and Genomics (KEGG) pathway enrichment analysis. Molecular docking was used to verify the binding affinity between the core targets and the bioactive ingredients. HUVEC viability, inflammatory response and mRNA expression levels of core target genes were evaluated by cell counting kit 8 assay, enzyme-linked immunosorbent assay (ELISA) and qRT-PCR. A total of 60 candidate compounds and 325 predicted target genes were screened. PPI network analysis suggested that TP53, SRC, STAT3, and AKT1 may be the core targets. BYHWT in AS treatment was associated with 46 signaling pathways. GA120, baicalein, and 3,9-di-o-methylnissolin had good binding affinity with core target proteins. Baicalein treatment could significantly promoted the viability and repress the inflammatory response of HUVEC cells stimulated by ox-LDL. In addition, Baicalein can regulate the expression of core targets including AKT1, MAPK1, PIK3CA, JUN, TP53, SRC, EGFR, and ESR1. In conclusion, BYHWT and its main bioactive component baicalein, inhibit inflammatory response and modulate multiple downstream genes of endothelial cells, and show good potential to block the progression of AS and cardiovascular/cerebrovascular diseases.