In this study, we verified by bioinformatics analysis and subsequent experiments that lncRNA SEMA3B‐AS1 inhibited tumor angiogenesis by epigenetic regulating the expression of its sense gene SEMA3B, which further highlighted the importance of lncRNAs in epigenetic regulation and expanded the molecular mechanisms of CRC metastasis effected by lncRNAs. The gene discussed is SEMA3B; the disease is neoplasm.