Atherosclerosis is a chronic disease that thickens the blood vessel walls and narrows the lumen. Venous thrombosis is a blood clot that forms in the body’s deep veins or pulmonary arteries. However, the relationship between NDUFB11 and NDUFS3 and atherosclerosis and venous thrombosis is unclear. We employed data files that combined atherosclerosis and chronic stress groups. Subsequently, we conducted differential gene expression analysis (DEGs) and performed weighted gene co-expression network analysis (WGCNA). We constructed and analyzed a protein-protein interaction (PPI) network. Further analyses included functional enrichment analysis, gene set enrichment analysis (GSEA), gene expression heatmaps, immune infiltration analysis, and mRNA analysis. By comparing our findings with the Comparative Toxicogenomics Database (CTD), we identified the most relevant diseases associated with the core genes. Additionally, we utilized TargetScan to screen for miRNAs regulating the central DEGs. To validate our results, we conducted Western Blot experiments at the cellular level. A total of 1747 DEGs were co-identified. According to the Gene Ontology (GO) analysis of differentially expressed genes, they were primarily enriched in mitochondrial gene expression, mitochondrial envelope, organelle membrane, and mitochondrial inner membrane categories. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the target cells were mainly enriched in metabolic pathways, ribosomes, and histidine metabolism. The intersection of enriched terms from both GO and KEGG analyses showed significant enrichment in mitochondrial gene expression, mitochondrial envelope, organelle inner membrane, ribosomal structural constituents, histidine metabolism, and oxidative phosphorylation. Eight core genes were identified, including NDUFS5, UQCRQ, COX6C, COX7B, ATP5ME, NDUFS3, NDUFA3, and NDUFB11. The gene expression heatmap demonstrated that core genes (NDUFB11 and NDUFS3) were downregulated in atherosclerosis with venous thrombosis samples and upregulated in normal samples. CTD analysis revealed that the core genes NDUFB11 and NDUFS3 were associated with pain, arterial diseases, atherosclerosis, arteritis, venous thrombosis formation, and venous thromboembolism. We added Western Blot basic cell experiment for verification. NDUFB11 and NDUFS3 are downregulated in atherosclerosis and venous thrombosis, associated with poorer prognosis, and may serve as potential biomarkers for both diseases.